2013-07-16 20:21:33 -04:00
|
|
|
#
|
|
|
|
# Licensed to the Apache Software Foundation (ASF) under one or more
|
|
|
|
# contributor license agreements. See the NOTICE file distributed with
|
|
|
|
# this work for additional information regarding copyright ownership.
|
|
|
|
# The ASF licenses this file to You under the Apache License, Version 2.0
|
|
|
|
# (the "License"); you may not use this file except in compliance with
|
|
|
|
# the License. You may obtain a copy of the License at
|
|
|
|
#
|
|
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
#
|
|
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
|
|
# See the License for the specific language governing permissions and
|
|
|
|
# limitations under the License.
|
|
|
|
#
|
|
|
|
|
2012-12-27 22:59:04 -05:00
|
|
|
import copy
|
2013-08-23 14:16:44 -04:00
|
|
|
import sys
|
2015-04-16 19:20:57 -04:00
|
|
|
import os
|
|
|
|
import re
|
|
|
|
import operator
|
2012-08-25 21:00:25 -04:00
|
|
|
import shlex
|
2014-01-23 23:01:36 -05:00
|
|
|
import warnings
|
2014-04-03 18:42:17 -04:00
|
|
|
import heapq
|
2014-08-13 17:57:12 -04:00
|
|
|
import bisect
|
[SPARK-4327] [PySpark] Python API for RDD.randomSplit()
```
pyspark.RDD.randomSplit(self, weights, seed=None)
Randomly splits this RDD with the provided weights.
:param weights: weights for splits, will be normalized if they don't sum to 1
:param seed: random seed
:return: split RDDs in an list
>>> rdd = sc.parallelize(range(10), 1)
>>> rdd1, rdd2, rdd3 = rdd.randomSplit([0.4, 0.6, 1.0], 11)
>>> rdd1.collect()
[3, 6]
>>> rdd2.collect()
[0, 5, 7]
>>> rdd3.collect()
[1, 2, 4, 8, 9]
```
Author: Davies Liu <davies@databricks.com>
Closes #3193 from davies/randomSplit and squashes the following commits:
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-18 19:37:35 -05:00
|
|
|
import random
|
2015-03-09 19:24:06 -04:00
|
|
|
import socket
|
2015-04-16 19:20:57 -04:00
|
|
|
from subprocess import Popen, PIPE
|
|
|
|
from tempfile import NamedTemporaryFile
|
|
|
|
from threading import Thread
|
|
|
|
from collections import defaultdict
|
|
|
|
from itertools import chain
|
|
|
|
from functools import reduce
|
2015-01-28 20:26:03 -05:00
|
|
|
from math import sqrt, log, isinf, isnan, pow, ceil
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
if sys.version > '3':
|
|
|
|
basestring = unicode = str
|
|
|
|
else:
|
|
|
|
from itertools import imap as map, ifilter as filter
|
|
|
|
|
2013-11-05 20:52:39 -05:00
|
|
|
from pyspark.serializers import NoOpSerializer, CartesianDeserializer, \
|
2014-06-03 21:18:25 -04:00
|
|
|
BatchedSerializer, CloudPickleSerializer, PairDeserializer, \
|
2014-09-19 18:01:11 -04:00
|
|
|
PickleSerializer, pack_long, AutoBatchedSerializer
|
2012-08-10 04:10:02 -04:00
|
|
|
from pyspark.join import python_join, python_left_outer_join, \
|
2014-09-24 23:39:09 -04:00
|
|
|
python_right_outer_join, python_full_outer_join, python_cogroup
|
2013-08-20 16:22:06 -04:00
|
|
|
from pyspark.statcounter import StatCounter
|
[SPARK-4327] [PySpark] Python API for RDD.randomSplit()
```
pyspark.RDD.randomSplit(self, weights, seed=None)
Randomly splits this RDD with the provided weights.
:param weights: weights for splits, will be normalized if they don't sum to 1
:param seed: random seed
:return: split RDDs in an list
>>> rdd = sc.parallelize(range(10), 1)
>>> rdd1, rdd2, rdd3 = rdd.randomSplit([0.4, 0.6, 1.0], 11)
>>> rdd1.collect()
[3, 6]
>>> rdd2.collect()
[0, 5, 7]
>>> rdd3.collect()
[1, 2, 4, 8, 9]
```
Author: Davies Liu <davies@databricks.com>
Closes #3193 from davies/randomSplit and squashes the following commits:
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-18 19:37:35 -05:00
|
|
|
from pyspark.rddsampler import RDDSampler, RDDRangeSampler, RDDStratifiedSampler
|
2014-03-12 02:57:05 -04:00
|
|
|
from pyspark.storagelevel import StorageLevel
|
2014-04-08 21:15:52 -04:00
|
|
|
from pyspark.resultiterable import ResultIterable
|
2014-07-25 01:53:47 -04:00
|
|
|
from pyspark.shuffle import Aggregator, InMemoryMerger, ExternalMerger, \
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
get_used_memory, ExternalSorter, ExternalGroupBy
|
2014-09-15 22:28:17 -04:00
|
|
|
from pyspark.traceback_utils import SCCallSiteSync
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-10-22 13:28:59 -04:00
|
|
|
from py4j.java_collections import ListConverter, MapConverter
|
2012-08-25 16:59:01 -04:00
|
|
|
|
2014-09-03 14:49:45 -04:00
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
__all__ = ["RDD"]
|
|
|
|
|
2014-04-03 18:42:17 -04:00
|
|
|
|
2014-07-21 14:59:54 -04:00
|
|
|
def portable_hash(x):
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
This function returns consistent hash code for builtin types, especially
|
2014-07-21 14:59:54 -04:00
|
|
|
for None and tuple with None.
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
The algorithm is similar to that one used by CPython 2.7
|
2014-07-21 14:59:54 -04:00
|
|
|
|
|
|
|
>>> portable_hash(None)
|
|
|
|
0
|
2014-09-02 18:47:47 -04:00
|
|
|
>>> portable_hash((None, 1)) & 0xffffffff
|
2014-07-21 14:59:54 -04:00
|
|
|
219750521
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
if sys.version >= '3.3' and 'PYTHONHASHSEED' not in os.environ:
|
|
|
|
raise Exception("Randomness of hash of string should be disabled via PYTHONHASHSEED")
|
|
|
|
|
2014-07-21 14:59:54 -04:00
|
|
|
if x is None:
|
|
|
|
return 0
|
|
|
|
if isinstance(x, tuple):
|
|
|
|
h = 0x345678
|
|
|
|
for i in x:
|
|
|
|
h ^= portable_hash(i)
|
|
|
|
h *= 1000003
|
2015-04-16 19:20:57 -04:00
|
|
|
h &= sys.maxsize
|
2014-07-21 14:59:54 -04:00
|
|
|
h ^= len(x)
|
|
|
|
if h == -1:
|
|
|
|
h = -2
|
|
|
|
return h
|
|
|
|
return hash(x)
|
|
|
|
|
|
|
|
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
class BoundedFloat(float):
|
|
|
|
"""
|
|
|
|
Bounded value is generated by approximate job, with confidence and low
|
|
|
|
bound and high bound.
|
|
|
|
|
|
|
|
>>> BoundedFloat(100.0, 0.95, 95.0, 105.0)
|
|
|
|
100.0
|
|
|
|
"""
|
|
|
|
def __new__(cls, mean, confidence, low, high):
|
|
|
|
obj = float.__new__(cls, mean)
|
|
|
|
obj.confidence = confidence
|
|
|
|
obj.low = low
|
|
|
|
obj.high = high
|
|
|
|
return obj
|
|
|
|
|
|
|
|
|
2014-07-25 01:53:47 -04:00
|
|
|
def _parse_memory(s):
|
|
|
|
"""
|
|
|
|
Parse a memory string in the format supported by Java (e.g. 1g, 200m) and
|
|
|
|
return the value in MB
|
|
|
|
|
|
|
|
>>> _parse_memory("256m")
|
|
|
|
256
|
|
|
|
>>> _parse_memory("2g")
|
|
|
|
2048
|
|
|
|
"""
|
|
|
|
units = {'g': 1024, 'm': 1, 't': 1 << 20, 'k': 1.0 / 1024}
|
|
|
|
if s[-1] not in units:
|
|
|
|
raise ValueError("invalid format: " + s)
|
|
|
|
return int(float(s[:-1]) * units[s[-1].lower()])
|
|
|
|
|
|
|
|
|
2015-03-09 19:24:06 -04:00
|
|
|
def _load_from_socket(port, serializer):
|
|
|
|
sock = socket.socket()
|
2015-04-02 15:18:33 -04:00
|
|
|
sock.settimeout(3)
|
2015-03-09 19:24:06 -04:00
|
|
|
try:
|
|
|
|
sock.connect(("localhost", port))
|
|
|
|
rf = sock.makefile("rb", 65536)
|
|
|
|
for item in serializer.load_stream(rf):
|
|
|
|
yield item
|
|
|
|
finally:
|
|
|
|
sock.close()
|
|
|
|
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
def ignore_unicode_prefix(f):
|
|
|
|
"""
|
|
|
|
Ignore the 'u' prefix of string in doc tests, to make it works
|
|
|
|
in both python 2 and 3
|
|
|
|
"""
|
|
|
|
if sys.version >= '3':
|
|
|
|
# the representation of unicode string in Python 3 does not have prefix 'u',
|
|
|
|
# so remove the prefix 'u' for doc tests
|
|
|
|
literal_re = re.compile(r"(\W|^)[uU](['])", re.UNICODE)
|
|
|
|
f.__doc__ = literal_re.sub(r'\1\2', f.__doc__)
|
|
|
|
return f
|
|
|
|
|
|
|
|
|
2015-02-17 19:54:57 -05:00
|
|
|
class Partitioner(object):
|
|
|
|
def __init__(self, numPartitions, partitionFunc):
|
|
|
|
self.numPartitions = numPartitions
|
|
|
|
self.partitionFunc = partitionFunc
|
|
|
|
|
|
|
|
def __eq__(self, other):
|
|
|
|
return (isinstance(other, Partitioner) and self.numPartitions == other.numPartitions
|
|
|
|
and self.partitionFunc == other.partitionFunc)
|
|
|
|
|
|
|
|
def __call__(self, k):
|
|
|
|
return self.partitionFunc(k) % self.numPartitions
|
|
|
|
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
class RDD(object):
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
|
|
|
A Resilient Distributed Dataset (RDD), the basic abstraction in Spark.
|
|
|
|
Represents an immutable, partitioned collection of elements that can be
|
|
|
|
operated on in parallel.
|
|
|
|
"""
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-11-04 02:56:14 -05:00
|
|
|
def __init__(self, jrdd, ctx, jrdd_deserializer=AutoBatchedSerializer(PickleSerializer())):
|
2012-08-10 04:10:02 -04:00
|
|
|
self._jrdd = jrdd
|
|
|
|
self.is_cached = False
|
2013-01-20 16:59:45 -05:00
|
|
|
self.is_checkpointed = False
|
2012-08-10 04:10:02 -04:00
|
|
|
self.ctx = ctx
|
2013-11-05 20:52:39 -05:00
|
|
|
self._jrdd_deserializer = jrdd_deserializer
|
2014-03-06 15:45:27 -05:00
|
|
|
self._id = jrdd.id()
|
2015-02-17 19:54:57 -05:00
|
|
|
self.partitioner = None
|
2014-03-06 15:45:27 -05:00
|
|
|
|
2014-11-04 02:56:14 -05:00
|
|
|
def _pickled(self):
|
|
|
|
return self._reserialize(AutoBatchedSerializer(PickleSerializer()))
|
2014-07-30 16:19:05 -04:00
|
|
|
|
2014-03-06 15:45:27 -05:00
|
|
|
def id(self):
|
|
|
|
"""
|
|
|
|
A unique ID for this RDD (within its SparkContext).
|
|
|
|
"""
|
|
|
|
return self._id
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2013-12-19 07:38:20 -05:00
|
|
|
def __repr__(self):
|
|
|
|
return self._jrdd.toString()
|
|
|
|
|
2015-01-23 20:53:15 -05:00
|
|
|
def __getnewargs__(self):
|
|
|
|
# This method is called when attempting to pickle an RDD, which is always an error:
|
|
|
|
raise Exception(
|
|
|
|
"It appears that you are attempting to broadcast an RDD or reference an RDD from an "
|
|
|
|
"action or transformation. RDD transformations and actions can only be invoked by the "
|
|
|
|
"driver, not inside of other transformations; for example, "
|
|
|
|
"rdd1.map(lambda x: rdd2.values.count() * x) is invalid because the values "
|
|
|
|
"transformation and count action cannot be performed inside of the rdd1.map "
|
|
|
|
"transformation. For more information, see SPARK-5063."
|
|
|
|
)
|
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
@property
|
|
|
|
def context(self):
|
|
|
|
"""
|
|
|
|
The L{SparkContext} that this RDD was created on.
|
|
|
|
"""
|
|
|
|
return self.ctx
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
def cache(self):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2014-07-24 21:15:37 -04:00
|
|
|
Persist this RDD with the default storage level (C{MEMORY_ONLY_SER}).
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2012-08-10 04:10:02 -04:00
|
|
|
self.is_cached = True
|
2014-07-24 21:15:37 -04:00
|
|
|
self.persist(StorageLevel.MEMORY_ONLY_SER)
|
2012-08-10 04:10:02 -04:00
|
|
|
return self
|
|
|
|
|
2014-09-06 17:49:25 -04:00
|
|
|
def persist(self, storageLevel=StorageLevel.MEMORY_ONLY_SER):
|
2013-09-06 02:36:27 -04:00
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Set this RDD's storage level to persist its values across operations
|
|
|
|
after the first time it is computed. This can only be used to assign
|
|
|
|
a new storage level if the RDD does not have a storage level set yet.
|
2014-09-06 17:49:25 -04:00
|
|
|
If no storage level is specified defaults to (C{MEMORY_ONLY_SER}).
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize(["b", "a", "c"])
|
|
|
|
>>> rdd.persist().is_cached
|
|
|
|
True
|
2013-09-06 02:36:27 -04:00
|
|
|
"""
|
|
|
|
self.is_cached = True
|
2013-09-07 17:41:31 -04:00
|
|
|
javaStorageLevel = self.ctx._getJavaStorageLevel(storageLevel)
|
|
|
|
self._jrdd.persist(javaStorageLevel)
|
2013-09-06 02:36:27 -04:00
|
|
|
return self
|
|
|
|
|
|
|
|
def unpersist(self):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Mark the RDD as non-persistent, and remove all blocks for it from
|
|
|
|
memory and disk.
|
2013-09-06 02:36:27 -04:00
|
|
|
"""
|
|
|
|
self.is_cached = False
|
|
|
|
self._jrdd.unpersist()
|
|
|
|
return self
|
|
|
|
|
2013-01-16 22:15:14 -05:00
|
|
|
def checkpoint(self):
|
|
|
|
"""
|
2013-01-20 18:31:41 -05:00
|
|
|
Mark this RDD for checkpointing. It will be saved to a file inside the
|
|
|
|
checkpoint directory set with L{SparkContext.setCheckpointDir()} and
|
|
|
|
all references to its parent RDDs will be removed. This function must
|
|
|
|
be called before any job has been executed on this RDD. It is strongly
|
|
|
|
recommended that this RDD is persisted in memory, otherwise saving it
|
2013-01-16 22:15:14 -05:00
|
|
|
on a file will require recomputation.
|
|
|
|
"""
|
2013-01-20 16:59:45 -05:00
|
|
|
self.is_checkpointed = True
|
2013-01-16 22:15:14 -05:00
|
|
|
self._jrdd.rdd().checkpoint()
|
|
|
|
|
|
|
|
def isCheckpointed(self):
|
|
|
|
"""
|
|
|
|
Return whether this RDD has been checkpointed or not
|
|
|
|
"""
|
|
|
|
return self._jrdd.rdd().isCheckpointed()
|
|
|
|
|
|
|
|
def getCheckpointFile(self):
|
|
|
|
"""
|
|
|
|
Gets the name of the file to which this RDD was checkpointed
|
|
|
|
"""
|
|
|
|
checkpointFile = self._jrdd.rdd().getCheckpointFile()
|
|
|
|
if checkpointFile.isDefined():
|
|
|
|
return checkpointFile.get()
|
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
def map(self, f, preservesPartitioning=False):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2014-03-04 18:32:43 -05:00
|
|
|
Return a new RDD by applying a function to each element of this RDD.
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2014-03-19 17:04:45 -04:00
|
|
|
>>> rdd = sc.parallelize(["b", "a", "c"])
|
|
|
|
>>> sorted(rdd.map(lambda x: (x, 1)).collect())
|
|
|
|
[('a', 1), ('b', 1), ('c', 1)]
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
[SPARK-2010] [PySpark] [SQL] support nested structure in SchemaRDD
Convert Row in JavaSchemaRDD into Array[Any] and unpickle them as tuple in Python, then convert them into namedtuple, so use can access fields just like attributes.
This will let nested structure can be accessed as object, also it will reduce the size of serialized data and better performance.
root
|-- field1: integer (nullable = true)
|-- field2: string (nullable = true)
|-- field3: struct (nullable = true)
| |-- field4: integer (nullable = true)
| |-- field5: array (nullable = true)
| | |-- element: integer (containsNull = false)
|-- field6: array (nullable = true)
| |-- element: struct (containsNull = false)
| | |-- field7: string (nullable = true)
Then we can access them by row.field3.field5[0] or row.field6[5].field7
It also will infer the schema in Python, convert Row/dict/namedtuple/objects into tuple before serialization, then call applySchema in JVM. During inferSchema(), the top level of dict in row will be StructType, but any nested dictionary will be MapType.
You can use pyspark.sql.Row to convert unnamed structure into Row object, make the RDD can be inferable. Such as:
ctx.inferSchema(rdd.map(lambda x: Row(a=x[0], b=x[1]))
Or you could use Row to create a class just like namedtuple, for example:
Person = Row("name", "age")
ctx.inferSchema(rdd.map(lambda x: Person(*x)))
Also, you can call applySchema to apply an schema to a RDD of tuple/list and turn it into a SchemaRDD. The `schema` should be StructType, see the API docs for details.
schema = StructType([StructField("name, StringType, True),
StructType("age", IntegerType, True)])
ctx.applySchema(rdd, schema)
PS: In order to use namedtuple to inferSchema, you should make namedtuple picklable.
Author: Davies Liu <davies.liu@gmail.com>
Closes #1598 from davies/nested and squashes the following commits:
f1d15b6 [Davies Liu] verify schema with the first few rows
8852aaf [Davies Liu] check type of schema
abe9e6e [Davies Liu] address comments
61b2292 [Davies Liu] add @deprecated to pythonToJavaMap
1e5b801 [Davies Liu] improve cache of classes
51aa135 [Davies Liu] use Row to infer schema
e9c0d5c [Davies Liu] remove string typed schema
353a3f2 [Davies Liu] fix code style
63de8f8 [Davies Liu] fix typo
c79ca67 [Davies Liu] fix serialization of nested data
6b258b5 [Davies Liu] fix pep8
9d8447c [Davies Liu] apply schema provided by string of names
f5df97f [Davies Liu] refactor, address comments
9d9af55 [Davies Liu] use arrry to applySchema and infer schema in Python
84679b3 [Davies Liu] Merge branch 'master' of github.com:apache/spark into nested
0eaaf56 [Davies Liu] fix doc tests
b3559b4 [Davies Liu] use generated Row instead of namedtuple
c4ddc30 [Davies Liu] fix conflict between name of fields and variables
7f6f251 [Davies Liu] address all comments
d69d397 [Davies Liu] refactor
2cc2d45 [Davies Liu] refactor
182fb46 [Davies Liu] refactor
bc6e9e1 [Davies Liu] switch to new Schema API
547bf3e [Davies Liu] Merge branch 'master' into nested
a435b5a [Davies Liu] add docs and code refactor
2c8debc [Davies Liu] Merge branch 'master' into nested
644665a [Davies Liu] use tuple and namedtuple for schemardd
2014-08-01 21:47:41 -04:00
|
|
|
def func(_, iterator):
|
2015-04-16 19:20:57 -04:00
|
|
|
return map(f, iterator)
|
[SPARK-2010] [PySpark] [SQL] support nested structure in SchemaRDD
Convert Row in JavaSchemaRDD into Array[Any] and unpickle them as tuple in Python, then convert them into namedtuple, so use can access fields just like attributes.
This will let nested structure can be accessed as object, also it will reduce the size of serialized data and better performance.
root
|-- field1: integer (nullable = true)
|-- field2: string (nullable = true)
|-- field3: struct (nullable = true)
| |-- field4: integer (nullable = true)
| |-- field5: array (nullable = true)
| | |-- element: integer (containsNull = false)
|-- field6: array (nullable = true)
| |-- element: struct (containsNull = false)
| | |-- field7: string (nullable = true)
Then we can access them by row.field3.field5[0] or row.field6[5].field7
It also will infer the schema in Python, convert Row/dict/namedtuple/objects into tuple before serialization, then call applySchema in JVM. During inferSchema(), the top level of dict in row will be StructType, but any nested dictionary will be MapType.
You can use pyspark.sql.Row to convert unnamed structure into Row object, make the RDD can be inferable. Such as:
ctx.inferSchema(rdd.map(lambda x: Row(a=x[0], b=x[1]))
Or you could use Row to create a class just like namedtuple, for example:
Person = Row("name", "age")
ctx.inferSchema(rdd.map(lambda x: Person(*x)))
Also, you can call applySchema to apply an schema to a RDD of tuple/list and turn it into a SchemaRDD. The `schema` should be StructType, see the API docs for details.
schema = StructType([StructField("name, StringType, True),
StructType("age", IntegerType, True)])
ctx.applySchema(rdd, schema)
PS: In order to use namedtuple to inferSchema, you should make namedtuple picklable.
Author: Davies Liu <davies.liu@gmail.com>
Closes #1598 from davies/nested and squashes the following commits:
f1d15b6 [Davies Liu] verify schema with the first few rows
8852aaf [Davies Liu] check type of schema
abe9e6e [Davies Liu] address comments
61b2292 [Davies Liu] add @deprecated to pythonToJavaMap
1e5b801 [Davies Liu] improve cache of classes
51aa135 [Davies Liu] use Row to infer schema
e9c0d5c [Davies Liu] remove string typed schema
353a3f2 [Davies Liu] fix code style
63de8f8 [Davies Liu] fix typo
c79ca67 [Davies Liu] fix serialization of nested data
6b258b5 [Davies Liu] fix pep8
9d8447c [Davies Liu] apply schema provided by string of names
f5df97f [Davies Liu] refactor, address comments
9d9af55 [Davies Liu] use arrry to applySchema and infer schema in Python
84679b3 [Davies Liu] Merge branch 'master' of github.com:apache/spark into nested
0eaaf56 [Davies Liu] fix doc tests
b3559b4 [Davies Liu] use generated Row instead of namedtuple
c4ddc30 [Davies Liu] fix conflict between name of fields and variables
7f6f251 [Davies Liu] address all comments
d69d397 [Davies Liu] refactor
2cc2d45 [Davies Liu] refactor
182fb46 [Davies Liu] refactor
bc6e9e1 [Davies Liu] switch to new Schema API
547bf3e [Davies Liu] Merge branch 'master' into nested
a435b5a [Davies Liu] add docs and code refactor
2c8debc [Davies Liu] Merge branch 'master' into nested
644665a [Davies Liu] use tuple and namedtuple for schemardd
2014-08-01 21:47:41 -04:00
|
|
|
return self.mapPartitionsWithIndex(func, preservesPartitioning)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
def flatMap(self, f, preservesPartitioning=False):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return a new RDD by first applying a function to all elements of this
|
|
|
|
RDD, and then flattening the results.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> rdd = sc.parallelize([2, 3, 4])
|
|
|
|
>>> sorted(rdd.flatMap(lambda x: range(1, x)).collect())
|
|
|
|
[1, 1, 1, 2, 2, 3]
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> sorted(rdd.flatMap(lambda x: [(x, x), (x, x)]).collect())
|
2012-08-10 04:10:02 -04:00
|
|
|
[(2, 2), (2, 2), (3, 3), (3, 3), (4, 4), (4, 4)]
|
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
def func(s, iterator):
|
2015-04-16 19:20:57 -04:00
|
|
|
return chain.from_iterable(map(f, iterator))
|
2014-01-23 23:01:36 -05:00
|
|
|
return self.mapPartitionsWithIndex(func, preservesPartitioning)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
def mapPartitions(self, f, preservesPartitioning=False):
|
2012-08-25 01:51:45 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return a new RDD by applying a function to each partition of this RDD.
|
|
|
|
|
2012-08-25 01:51:45 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4], 2)
|
|
|
|
>>> def f(iterator): yield sum(iterator)
|
|
|
|
>>> rdd.mapPartitions(f).collect()
|
|
|
|
[3, 7]
|
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
def func(s, iterator):
|
|
|
|
return f(iterator)
|
2014-08-27 16:18:33 -04:00
|
|
|
return self.mapPartitionsWithIndex(func, preservesPartitioning)
|
2014-01-23 23:01:36 -05:00
|
|
|
|
|
|
|
def mapPartitionsWithIndex(self, f, preservesPartitioning=False):
|
|
|
|
"""
|
|
|
|
Return a new RDD by applying a function to each partition of this RDD,
|
|
|
|
while tracking the index of the original partition.
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4], 4)
|
|
|
|
>>> def f(splitIndex, iterator): yield splitIndex
|
|
|
|
>>> rdd.mapPartitionsWithIndex(f).sum()
|
|
|
|
6
|
|
|
|
"""
|
|
|
|
return PipelinedRDD(self, f, preservesPartitioning)
|
2013-01-08 19:04:41 -05:00
|
|
|
|
|
|
|
def mapPartitionsWithSplit(self, f, preservesPartitioning=False):
|
|
|
|
"""
|
2014-01-23 23:01:36 -05:00
|
|
|
Deprecated: use mapPartitionsWithIndex instead.
|
|
|
|
|
2013-01-08 19:04:41 -05:00
|
|
|
Return a new RDD by applying a function to each partition of this RDD,
|
|
|
|
while tracking the index of the original partition.
|
2012-12-27 20:55:33 -05:00
|
|
|
|
2013-01-08 19:04:41 -05:00
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4], 4)
|
|
|
|
>>> def f(splitIndex, iterator): yield splitIndex
|
|
|
|
>>> rdd.mapPartitionsWithSplit(f).sum()
|
|
|
|
6
|
|
|
|
"""
|
2014-01-23 23:01:36 -05:00
|
|
|
warnings.warn("mapPartitionsWithSplit is deprecated; "
|
2014-07-14 03:42:59 -04:00
|
|
|
"use mapPartitionsWithIndex instead", DeprecationWarning, stacklevel=2)
|
2014-01-23 23:01:36 -05:00
|
|
|
return self.mapPartitionsWithIndex(f, preservesPartitioning)
|
2012-08-25 01:51:45 -04:00
|
|
|
|
2014-06-09 03:08:40 -04:00
|
|
|
def getNumPartitions(self):
|
2014-07-14 03:42:59 -04:00
|
|
|
"""
|
|
|
|
Returns the number of partitions in RDD
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2014-07-14 03:42:59 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4], 2)
|
|
|
|
>>> rdd.getNumPartitions()
|
|
|
|
2
|
|
|
|
"""
|
|
|
|
return self._jrdd.partitions().size()
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
def filter(self, f):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return a new RDD containing only the elements that satisfy a predicate.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4, 5])
|
|
|
|
>>> rdd.filter(lambda x: x % 2 == 0).collect()
|
|
|
|
[2, 4]
|
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
def func(iterator):
|
2015-04-16 19:20:57 -04:00
|
|
|
return filter(f, iterator)
|
2014-08-27 16:18:33 -04:00
|
|
|
return self.mapPartitions(func, True)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-09-16 14:39:57 -04:00
|
|
|
def distinct(self, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return a new RDD containing the distinct elements in this RDD.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> sorted(sc.parallelize([1, 1, 2, 3]).distinct().collect())
|
|
|
|
[1, 2, 3]
|
|
|
|
"""
|
2013-07-28 23:50:38 -04:00
|
|
|
return self.map(lambda x: (x, None)) \
|
2014-09-16 14:39:57 -04:00
|
|
|
.reduceByKey(lambda x, _: x, numPartitions) \
|
2015-04-16 19:20:57 -04:00
|
|
|
.map(lambda x: x[0])
|
2012-08-10 04:10:02 -04:00
|
|
|
|
SPARK-1438 RDD.sample() make seed param optional
copying form previous pull request https://github.com/apache/spark/pull/462
Its probably better to let the underlying language implementation take care of the default . This was easier to do with python as the default value for seed in random and numpy random is None.
In Scala/Java side it might mean propagating an Option or null(oh no!) down the chain until where the Random is constructed. But, looks like the convention in some other methods was to use System.nanoTime. So, followed that convention.
Conflict with overloaded method in sql.SchemaRDD.sample which also defines default params.
sample(fraction, withReplacement=false, seed=math.random)
Scala does not allow more than one overloaded to have default params. I believe the author intended to override the RDD.sample method and not overload it. So, changed it.
If backward compatible is important, 3 new method can be introduced (without default params) like this
sample(fraction)
sample(fraction, withReplacement)
sample(fraction, withReplacement, seed)
Added some tests for the scala RDD takeSample method.
Author: Arun Ramakrishnan <smartnut007@gmail.com>
This patch had conflicts when merged, resolved by
Committer: Matei Zaharia <matei@databricks.com>
Closes #477 from smartnut007/master and squashes the following commits:
07bb06e [Arun Ramakrishnan] SPARK-1438 fixing more space formatting issues
b9ebfe2 [Arun Ramakrishnan] SPARK-1438 removing redundant import of random in python rddsampler
8d05b1a [Arun Ramakrishnan] SPARK-1438 RDD . Replace System.nanoTime with a Random generated number. python: use a separate instance of Random instead of seeding language api global Random instance.
69619c6 [Arun Ramakrishnan] SPARK-1438 fix spacing issue
0c247db [Arun Ramakrishnan] SPARK-1438 RDD language apis to support optional seed in RDD methods sample/takeSample
2014-04-24 20:27:16 -04:00
|
|
|
def sample(self, withReplacement, fraction, seed=None):
|
2013-08-23 14:16:44 -04:00
|
|
|
"""
|
[SPARK-4477] [PySpark] remove numpy from RDDSampler
In RDDSampler, it try use numpy to gain better performance for possion(), but the number of call of random() is only (1+faction) * N in the pure python implementation of possion(), so there is no much performance gain from numpy.
numpy is not a dependent of pyspark, so it maybe introduce some problem, such as there is no numpy installed in slaves, but only installed master, as reported in SPARK-927.
It also complicate the code a lot, so we may should remove numpy from RDDSampler.
I also did some benchmark to verify that:
```
>>> from pyspark.mllib.random import RandomRDDs
>>> rdd = RandomRDDs.uniformRDD(sc, 1 << 20, 1).cache()
>>> rdd.count() # cache it
>>> rdd.sample(True, 0.9).count() # measure this line
```
the results:
|withReplacement | random | numpy.random |
------- | ------------ | -------
|True | 1.5 s| 1.4 s|
|False| 0.6 s | 0.8 s|
closes #2313
Note: this patch including some commits that not mirrored to github, it will be OK after it catches up.
Author: Davies Liu <davies@databricks.com>
Author: Xiangrui Meng <meng@databricks.com>
Closes #3351 from davies/numpy and squashes the following commits:
5c438d7 [Davies Liu] fix comment
c5b9252 [Davies Liu] Merge pull request #1 from mengxr/SPARK-4477
98eb31b [Xiangrui Meng] make poisson sampling slightly faster
ee17d78 [Davies Liu] remove = for float
13f7b05 [Davies Liu] Merge branch 'master' of http://git-wip-us.apache.org/repos/asf/spark into numpy
f583023 [Davies Liu] fix tests
51649f5 [Davies Liu] remove numpy in RDDSampler
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-20 19:40:25 -05:00
|
|
|
Return a sampled subset of this RDD.
|
|
|
|
|
2015-03-20 14:30:45 -04:00
|
|
|
:param withReplacement: can elements be sampled multiple times (replaced when sampled out)
|
|
|
|
:param fraction: expected size of the sample as a fraction of this RDD's size
|
|
|
|
without replacement: probability that each element is chosen; fraction must be [0, 1]
|
|
|
|
with replacement: expected number of times each element is chosen; fraction must be >= 0
|
|
|
|
:param seed: seed for the random number generator
|
|
|
|
|
[SPARK-4477] [PySpark] remove numpy from RDDSampler
In RDDSampler, it try use numpy to gain better performance for possion(), but the number of call of random() is only (1+faction) * N in the pure python implementation of possion(), so there is no much performance gain from numpy.
numpy is not a dependent of pyspark, so it maybe introduce some problem, such as there is no numpy installed in slaves, but only installed master, as reported in SPARK-927.
It also complicate the code a lot, so we may should remove numpy from RDDSampler.
I also did some benchmark to verify that:
```
>>> from pyspark.mllib.random import RandomRDDs
>>> rdd = RandomRDDs.uniformRDD(sc, 1 << 20, 1).cache()
>>> rdd.count() # cache it
>>> rdd.sample(True, 0.9).count() # measure this line
```
the results:
|withReplacement | random | numpy.random |
------- | ------------ | -------
|True | 1.5 s| 1.4 s|
|False| 0.6 s | 0.8 s|
closes #2313
Note: this patch including some commits that not mirrored to github, it will be OK after it catches up.
Author: Davies Liu <davies@databricks.com>
Author: Xiangrui Meng <meng@databricks.com>
Closes #3351 from davies/numpy and squashes the following commits:
5c438d7 [Davies Liu] fix comment
c5b9252 [Davies Liu] Merge pull request #1 from mengxr/SPARK-4477
98eb31b [Xiangrui Meng] make poisson sampling slightly faster
ee17d78 [Davies Liu] remove = for float
13f7b05 [Davies Liu] Merge branch 'master' of http://git-wip-us.apache.org/repos/asf/spark into numpy
f583023 [Davies Liu] fix tests
51649f5 [Davies Liu] remove numpy in RDDSampler
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-20 19:40:25 -05:00
|
|
|
>>> rdd = sc.parallelize(range(100), 4)
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> 6 <= rdd.sample(False, 0.1, 81).count() <= 14
|
|
|
|
True
|
2013-08-23 14:16:44 -04:00
|
|
|
"""
|
2014-07-25 02:42:08 -04:00
|
|
|
assert fraction >= 0.0, "Negative fraction value: %s" % fraction
|
2014-01-23 23:01:36 -05:00
|
|
|
return self.mapPartitionsWithIndex(RDDSampler(withReplacement, fraction, seed).func, True)
|
2013-08-23 14:16:44 -04:00
|
|
|
|
[SPARK-4327] [PySpark] Python API for RDD.randomSplit()
```
pyspark.RDD.randomSplit(self, weights, seed=None)
Randomly splits this RDD with the provided weights.
:param weights: weights for splits, will be normalized if they don't sum to 1
:param seed: random seed
:return: split RDDs in an list
>>> rdd = sc.parallelize(range(10), 1)
>>> rdd1, rdd2, rdd3 = rdd.randomSplit([0.4, 0.6, 1.0], 11)
>>> rdd1.collect()
[3, 6]
>>> rdd2.collect()
[0, 5, 7]
>>> rdd3.collect()
[1, 2, 4, 8, 9]
```
Author: Davies Liu <davies@databricks.com>
Closes #3193 from davies/randomSplit and squashes the following commits:
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-18 19:37:35 -05:00
|
|
|
def randomSplit(self, weights, seed=None):
|
|
|
|
"""
|
|
|
|
Randomly splits this RDD with the provided weights.
|
|
|
|
|
|
|
|
:param weights: weights for splits, will be normalized if they don't sum to 1
|
|
|
|
:param seed: random seed
|
|
|
|
:return: split RDDs in a list
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> rdd = sc.parallelize(range(500), 1)
|
[SPARK-4327] [PySpark] Python API for RDD.randomSplit()
```
pyspark.RDD.randomSplit(self, weights, seed=None)
Randomly splits this RDD with the provided weights.
:param weights: weights for splits, will be normalized if they don't sum to 1
:param seed: random seed
:return: split RDDs in an list
>>> rdd = sc.parallelize(range(10), 1)
>>> rdd1, rdd2, rdd3 = rdd.randomSplit([0.4, 0.6, 1.0], 11)
>>> rdd1.collect()
[3, 6]
>>> rdd2.collect()
[0, 5, 7]
>>> rdd3.collect()
[1, 2, 4, 8, 9]
```
Author: Davies Liu <davies@databricks.com>
Closes #3193 from davies/randomSplit and squashes the following commits:
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-18 19:37:35 -05:00
|
|
|
>>> rdd1, rdd2 = rdd.randomSplit([2, 3], 17)
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> len(rdd1.collect() + rdd2.collect())
|
|
|
|
500
|
|
|
|
>>> 150 < rdd1.count() < 250
|
|
|
|
True
|
|
|
|
>>> 250 < rdd2.count() < 350
|
|
|
|
True
|
[SPARK-4327] [PySpark] Python API for RDD.randomSplit()
```
pyspark.RDD.randomSplit(self, weights, seed=None)
Randomly splits this RDD with the provided weights.
:param weights: weights for splits, will be normalized if they don't sum to 1
:param seed: random seed
:return: split RDDs in an list
>>> rdd = sc.parallelize(range(10), 1)
>>> rdd1, rdd2, rdd3 = rdd.randomSplit([0.4, 0.6, 1.0], 11)
>>> rdd1.collect()
[3, 6]
>>> rdd2.collect()
[0, 5, 7]
>>> rdd3.collect()
[1, 2, 4, 8, 9]
```
Author: Davies Liu <davies@databricks.com>
Closes #3193 from davies/randomSplit and squashes the following commits:
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-18 19:37:35 -05:00
|
|
|
"""
|
|
|
|
s = float(sum(weights))
|
|
|
|
cweights = [0.0]
|
|
|
|
for w in weights:
|
|
|
|
cweights.append(cweights[-1] + w / s)
|
|
|
|
if seed is None:
|
|
|
|
seed = random.randint(0, 2 ** 32 - 1)
|
|
|
|
return [self.mapPartitionsWithIndex(RDDRangeSampler(lb, ub, seed).func, True)
|
|
|
|
for lb, ub in zip(cweights, cweights[1:])]
|
|
|
|
|
2013-08-23 14:16:44 -04:00
|
|
|
# this is ported from scala/spark/RDD.scala
|
SPARK-1438 RDD.sample() make seed param optional
copying form previous pull request https://github.com/apache/spark/pull/462
Its probably better to let the underlying language implementation take care of the default . This was easier to do with python as the default value for seed in random and numpy random is None.
In Scala/Java side it might mean propagating an Option or null(oh no!) down the chain until where the Random is constructed. But, looks like the convention in some other methods was to use System.nanoTime. So, followed that convention.
Conflict with overloaded method in sql.SchemaRDD.sample which also defines default params.
sample(fraction, withReplacement=false, seed=math.random)
Scala does not allow more than one overloaded to have default params. I believe the author intended to override the RDD.sample method and not overload it. So, changed it.
If backward compatible is important, 3 new method can be introduced (without default params) like this
sample(fraction)
sample(fraction, withReplacement)
sample(fraction, withReplacement, seed)
Added some tests for the scala RDD takeSample method.
Author: Arun Ramakrishnan <smartnut007@gmail.com>
This patch had conflicts when merged, resolved by
Committer: Matei Zaharia <matei@databricks.com>
Closes #477 from smartnut007/master and squashes the following commits:
07bb06e [Arun Ramakrishnan] SPARK-1438 fixing more space formatting issues
b9ebfe2 [Arun Ramakrishnan] SPARK-1438 removing redundant import of random in python rddsampler
8d05b1a [Arun Ramakrishnan] SPARK-1438 RDD . Replace System.nanoTime with a Random generated number. python: use a separate instance of Random instead of seeding language api global Random instance.
69619c6 [Arun Ramakrishnan] SPARK-1438 fix spacing issue
0c247db [Arun Ramakrishnan] SPARK-1438 RDD language apis to support optional seed in RDD methods sample/takeSample
2014-04-24 20:27:16 -04:00
|
|
|
def takeSample(self, withReplacement, num, seed=None):
|
2013-08-23 14:16:44 -04:00
|
|
|
"""
|
[SPARK-4477] [PySpark] remove numpy from RDDSampler
In RDDSampler, it try use numpy to gain better performance for possion(), but the number of call of random() is only (1+faction) * N in the pure python implementation of possion(), so there is no much performance gain from numpy.
numpy is not a dependent of pyspark, so it maybe introduce some problem, such as there is no numpy installed in slaves, but only installed master, as reported in SPARK-927.
It also complicate the code a lot, so we may should remove numpy from RDDSampler.
I also did some benchmark to verify that:
```
>>> from pyspark.mllib.random import RandomRDDs
>>> rdd = RandomRDDs.uniformRDD(sc, 1 << 20, 1).cache()
>>> rdd.count() # cache it
>>> rdd.sample(True, 0.9).count() # measure this line
```
the results:
|withReplacement | random | numpy.random |
------- | ------------ | -------
|True | 1.5 s| 1.4 s|
|False| 0.6 s | 0.8 s|
closes #2313
Note: this patch including some commits that not mirrored to github, it will be OK after it catches up.
Author: Davies Liu <davies@databricks.com>
Author: Xiangrui Meng <meng@databricks.com>
Closes #3351 from davies/numpy and squashes the following commits:
5c438d7 [Davies Liu] fix comment
c5b9252 [Davies Liu] Merge pull request #1 from mengxr/SPARK-4477
98eb31b [Xiangrui Meng] make poisson sampling slightly faster
ee17d78 [Davies Liu] remove = for float
13f7b05 [Davies Liu] Merge branch 'master' of http://git-wip-us.apache.org/repos/asf/spark into numpy
f583023 [Davies Liu] fix tests
51649f5 [Davies Liu] remove numpy in RDDSampler
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-20 19:40:25 -05:00
|
|
|
Return a fixed-size sampled subset of this RDD.
|
2013-08-23 14:16:44 -04:00
|
|
|
|
2014-06-12 22:44:27 -04:00
|
|
|
>>> rdd = sc.parallelize(range(0, 10))
|
|
|
|
>>> len(rdd.takeSample(True, 20, 1))
|
|
|
|
20
|
|
|
|
>>> len(rdd.takeSample(False, 5, 2))
|
|
|
|
5
|
|
|
|
>>> len(rdd.takeSample(False, 15, 3))
|
|
|
|
10
|
2013-08-23 14:16:44 -04:00
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
numStDev = 10.0
|
|
|
|
|
|
|
|
if num < 0:
|
|
|
|
raise ValueError("Sample size cannot be negative.")
|
|
|
|
elif num == 0:
|
|
|
|
return []
|
2013-08-23 14:16:44 -04:00
|
|
|
|
|
|
|
initialCount = self.count()
|
2014-06-12 22:44:27 -04:00
|
|
|
if initialCount == 0:
|
|
|
|
return []
|
2013-08-23 14:16:44 -04:00
|
|
|
|
[SPARK-4327] [PySpark] Python API for RDD.randomSplit()
```
pyspark.RDD.randomSplit(self, weights, seed=None)
Randomly splits this RDD with the provided weights.
:param weights: weights for splits, will be normalized if they don't sum to 1
:param seed: random seed
:return: split RDDs in an list
>>> rdd = sc.parallelize(range(10), 1)
>>> rdd1, rdd2, rdd3 = rdd.randomSplit([0.4, 0.6, 1.0], 11)
>>> rdd1.collect()
[3, 6]
>>> rdd2.collect()
[0, 5, 7]
>>> rdd3.collect()
[1, 2, 4, 8, 9]
```
Author: Davies Liu <davies@databricks.com>
Closes #3193 from davies/randomSplit and squashes the following commits:
78bf997 [Davies Liu] fix tests, do not use numpy in randomSplit, no performance gain
f5fdf63 [Davies Liu] fix bug with int in weights
4dfa2cd [Davies Liu] refactor
f866bcf [Davies Liu] remove unneeded change
c7a2007 [Davies Liu] switch to python implementation
95a48ac [Davies Liu] Merge branch 'master' of github.com:apache/spark into randomSplit
0d9b256 [Davies Liu] refactor
1715ee3 [Davies Liu] address comments
41fce54 [Davies Liu] randomSplit()
2014-11-18 19:37:35 -05:00
|
|
|
rand = random.Random(seed)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-06-12 22:44:27 -04:00
|
|
|
if (not withReplacement) and num >= initialCount:
|
|
|
|
# shuffle current RDD and return
|
|
|
|
samples = self.collect()
|
|
|
|
rand.shuffle(samples)
|
|
|
|
return samples
|
2014-03-17 01:14:59 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
maxSampleSize = sys.maxsize - int(numStDev * sqrt(sys.maxsize))
|
2014-06-12 22:44:27 -04:00
|
|
|
if num > maxSampleSize:
|
2014-07-14 03:42:59 -04:00
|
|
|
raise ValueError(
|
|
|
|
"Sample size cannot be greater than %d." % maxSampleSize)
|
2013-08-23 14:16:44 -04:00
|
|
|
|
2014-07-14 03:42:59 -04:00
|
|
|
fraction = RDD._computeFractionForSampleSize(
|
|
|
|
num, initialCount, withReplacement)
|
2013-08-23 14:16:44 -04:00
|
|
|
samples = self.sample(withReplacement, fraction, seed).collect()
|
2013-10-09 15:08:04 -04:00
|
|
|
|
2013-08-23 14:16:44 -04:00
|
|
|
# If the first sample didn't turn out large enough, keep trying to take samples;
|
|
|
|
# this shouldn't happen often because we use a big multiplier for their initial size.
|
|
|
|
# See: scala/spark/RDD.scala
|
2014-06-12 22:44:27 -04:00
|
|
|
while len(samples) < num:
|
|
|
|
# TODO: add log warning for when more than one iteration was run
|
2015-04-16 19:20:57 -04:00
|
|
|
seed = rand.randint(0, sys.maxsize)
|
2014-06-12 22:44:27 -04:00
|
|
|
samples = self.sample(withReplacement, fraction, seed).collect()
|
|
|
|
|
|
|
|
rand.shuffle(samples)
|
|
|
|
|
|
|
|
return samples[0:num]
|
|
|
|
|
|
|
|
@staticmethod
|
|
|
|
def _computeFractionForSampleSize(sampleSizeLowerBound, total, withReplacement):
|
|
|
|
"""
|
|
|
|
Returns a sampling rate that guarantees a sample of
|
|
|
|
size >= sampleSizeLowerBound 99.99% of the time.
|
|
|
|
|
|
|
|
How the sampling rate is determined:
|
|
|
|
Let p = num / total, where num is the sample size and total is the
|
|
|
|
total number of data points in the RDD. We're trying to compute
|
|
|
|
q > p such that
|
|
|
|
- when sampling with replacement, we're drawing each data point
|
|
|
|
with prob_i ~ Pois(q), where we want to guarantee
|
|
|
|
Pr[s < num] < 0.0001 for s = sum(prob_i for i from 0 to
|
|
|
|
total), i.e. the failure rate of not having a sufficiently large
|
|
|
|
sample < 0.0001. Setting q = p + 5 * sqrt(p/total) is sufficient
|
|
|
|
to guarantee 0.9999 success rate for num > 12, but we need a
|
|
|
|
slightly larger q (9 empirically determined).
|
|
|
|
- when sampling without replacement, we're drawing each data point
|
|
|
|
with prob_i ~ Binomial(total, fraction) and our choice of q
|
|
|
|
guarantees 1-delta, or 0.9999 success rate, where success rate is
|
|
|
|
defined the same as in sampling with replacement.
|
|
|
|
"""
|
|
|
|
fraction = float(sampleSizeLowerBound) / total
|
|
|
|
if withReplacement:
|
|
|
|
numStDev = 5
|
|
|
|
if (sampleSizeLowerBound < 12):
|
|
|
|
numStDev = 9
|
|
|
|
return fraction + numStDev * sqrt(fraction / total)
|
|
|
|
else:
|
|
|
|
delta = 0.00005
|
|
|
|
gamma = - log(delta) / total
|
|
|
|
return min(1, fraction + gamma + sqrt(gamma * gamma + 2 * gamma * fraction))
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
def union(self, other):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the union of this RDD and another one.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 1, 2, 3])
|
|
|
|
>>> rdd.union(rdd).collect()
|
|
|
|
[1, 1, 2, 3, 1, 1, 2, 3]
|
|
|
|
"""
|
2013-11-05 20:52:39 -05:00
|
|
|
if self._jrdd_deserializer == other._jrdd_deserializer:
|
|
|
|
rdd = RDD(self._jrdd.union(other._jrdd), self.ctx,
|
|
|
|
self._jrdd_deserializer)
|
|
|
|
else:
|
|
|
|
# These RDDs contain data in different serialized formats, so we
|
|
|
|
# must normalize them to the default serializer.
|
|
|
|
self_copy = self._reserialize()
|
|
|
|
other_copy = other._reserialize()
|
2015-02-17 19:54:57 -05:00
|
|
|
rdd = RDD(self_copy._jrdd.union(other_copy._jrdd), self.ctx,
|
|
|
|
self.ctx.serializer)
|
|
|
|
if (self.partitioner == other.partitioner and
|
|
|
|
self.getNumPartitions() == rdd.getNumPartitions()):
|
|
|
|
rdd.partitioner = self.partitioner
|
|
|
|
return rdd
|
2013-11-05 20:52:39 -05:00
|
|
|
|
2014-03-07 21:48:07 -05:00
|
|
|
def intersection(self, other):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Return the intersection of this RDD and another one. The output will
|
|
|
|
not contain any duplicate elements, even if the input RDDs did.
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2014-03-07 21:48:07 -05:00
|
|
|
Note that this method performs a shuffle internally.
|
|
|
|
|
|
|
|
>>> rdd1 = sc.parallelize([1, 10, 2, 3, 4, 5])
|
|
|
|
>>> rdd2 = sc.parallelize([1, 6, 2, 3, 7, 8])
|
|
|
|
>>> rdd1.intersection(rdd2).collect()
|
|
|
|
[1, 2, 3]
|
|
|
|
"""
|
|
|
|
return self.map(lambda v: (v, None)) \
|
|
|
|
.cogroup(other.map(lambda v: (v, None))) \
|
2015-04-16 19:20:57 -04:00
|
|
|
.filter(lambda k_vs: all(k_vs[1])) \
|
2014-03-07 21:48:07 -05:00
|
|
|
.keys()
|
|
|
|
|
2014-06-03 21:18:25 -04:00
|
|
|
def _reserialize(self, serializer=None):
|
|
|
|
serializer = serializer or self.ctx.serializer
|
2014-11-04 02:56:14 -05:00
|
|
|
if self._jrdd_deserializer != serializer:
|
2014-12-16 01:58:26 -05:00
|
|
|
self = self.map(lambda x: x, preservesPartitioning=True)
|
2014-11-04 02:56:14 -05:00
|
|
|
self._jrdd_deserializer = serializer
|
|
|
|
return self
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
def __add__(self, other):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the union of this RDD and another one.
|
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 1, 2, 3])
|
|
|
|
>>> (rdd + rdd).collect()
|
|
|
|
[1, 1, 2, 3, 1, 1, 2, 3]
|
|
|
|
"""
|
|
|
|
if not isinstance(other, RDD):
|
|
|
|
raise TypeError
|
|
|
|
return self.union(other)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-09-08 14:20:00 -04:00
|
|
|
def repartitionAndSortWithinPartitions(self, numPartitions=None, partitionFunc=portable_hash,
|
|
|
|
ascending=True, keyfunc=lambda x: x):
|
|
|
|
"""
|
|
|
|
Repartition the RDD according to the given partitioner and, within each resulting partition,
|
|
|
|
sort records by their keys.
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize([(0, 5), (3, 8), (2, 6), (0, 8), (3, 8), (1, 3)])
|
|
|
|
>>> rdd2 = rdd.repartitionAndSortWithinPartitions(2, lambda x: x % 2, 2)
|
|
|
|
>>> rdd2.glom().collect()
|
|
|
|
[[(0, 5), (0, 8), (2, 6)], [(1, 3), (3, 8), (3, 8)]]
|
|
|
|
"""
|
|
|
|
if numPartitions is None:
|
|
|
|
numPartitions = self._defaultReducePartitions()
|
|
|
|
|
|
|
|
spill = (self.ctx._conf.get("spark.shuffle.spill", 'True').lower() == "true")
|
|
|
|
memory = _parse_memory(self.ctx._conf.get("spark.python.worker.memory", "512m"))
|
|
|
|
serializer = self._jrdd_deserializer
|
|
|
|
|
|
|
|
def sortPartition(iterator):
|
|
|
|
sort = ExternalSorter(memory * 0.9, serializer).sorted if spill else sorted
|
2015-04-16 19:20:57 -04:00
|
|
|
return iter(sort(iterator, key=lambda k_v: keyfunc(k_v[0]), reverse=(not ascending)))
|
2014-09-08 14:20:00 -04:00
|
|
|
|
|
|
|
return self.partitionBy(numPartitions, partitionFunc).mapPartitions(sortPartition, True)
|
|
|
|
|
2014-07-14 03:42:59 -04:00
|
|
|
def sortByKey(self, ascending=True, numPartitions=None, keyfunc=lambda x: x):
|
2013-10-07 13:42:39 -04:00
|
|
|
"""
|
|
|
|
Sorts this RDD, which is assumed to consist of (key, value) pairs.
|
2014-07-14 03:42:59 -04:00
|
|
|
# noqa
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2013-10-07 13:42:39 -04:00
|
|
|
>>> tmp = [('a', 1), ('b', 2), ('1', 3), ('d', 4), ('2', 5)]
|
2014-08-20 01:43:49 -04:00
|
|
|
>>> sc.parallelize(tmp).sortByKey().first()
|
|
|
|
('1', 3)
|
2014-08-13 17:57:12 -04:00
|
|
|
>>> sc.parallelize(tmp).sortByKey(True, 1).collect()
|
|
|
|
[('1', 3), ('2', 5), ('a', 1), ('b', 2), ('d', 4)]
|
2013-10-07 13:42:39 -04:00
|
|
|
>>> sc.parallelize(tmp).sortByKey(True, 2).collect()
|
|
|
|
[('1', 3), ('2', 5), ('a', 1), ('b', 2), ('d', 4)]
|
|
|
|
>>> tmp2 = [('Mary', 1), ('had', 2), ('a', 3), ('little', 4), ('lamb', 5)]
|
|
|
|
>>> tmp2.extend([('whose', 6), ('fleece', 7), ('was', 8), ('white', 9)])
|
|
|
|
>>> sc.parallelize(tmp2).sortByKey(True, 3, keyfunc=lambda k: k.lower()).collect()
|
2014-07-14 03:42:59 -04:00
|
|
|
[('a', 3), ('fleece', 7), ('had', 2), ('lamb', 5),...('white', 9), ('whose', 6)]
|
2013-10-07 13:42:39 -04:00
|
|
|
"""
|
|
|
|
if numPartitions is None:
|
2014-06-20 03:06:57 -04:00
|
|
|
numPartitions = self._defaultReducePartitions()
|
2013-10-07 13:42:39 -04:00
|
|
|
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
spill = self._can_spill()
|
|
|
|
memory = self._memory_limit()
|
2014-08-26 19:57:40 -04:00
|
|
|
serializer = self._jrdd_deserializer
|
|
|
|
|
2014-08-20 01:43:49 -04:00
|
|
|
def sortPartition(iterator):
|
2014-08-26 19:57:40 -04:00
|
|
|
sort = ExternalSorter(memory * 0.9, serializer).sorted if spill else sorted
|
2015-04-16 19:20:57 -04:00
|
|
|
return iter(sort(iterator, key=lambda kv: keyfunc(kv[0]), reverse=(not ascending)))
|
2014-08-20 01:43:49 -04:00
|
|
|
|
2014-08-13 17:57:12 -04:00
|
|
|
if numPartitions == 1:
|
|
|
|
if self.getNumPartitions() > 1:
|
|
|
|
self = self.coalesce(1)
|
2014-08-27 16:18:33 -04:00
|
|
|
return self.mapPartitions(sortPartition, True)
|
2013-10-07 13:42:39 -04:00
|
|
|
|
|
|
|
# first compute the boundary of each part via sampling: we want to partition
|
|
|
|
# the key-space into bins such that the bins have roughly the same
|
|
|
|
# number of (key, value) pairs falling into them
|
2014-08-13 17:57:12 -04:00
|
|
|
rddSize = self.count()
|
2014-11-07 23:53:03 -05:00
|
|
|
if not rddSize:
|
|
|
|
return self # empty RDD
|
2014-08-13 17:57:12 -04:00
|
|
|
maxSampleSize = numPartitions * 20.0 # constant from Spark's RangePartitioner
|
|
|
|
fraction = min(maxSampleSize / max(rddSize, 1), 1.0)
|
2015-04-16 19:20:57 -04:00
|
|
|
samples = self.sample(False, fraction, 1).map(lambda kv: kv[0]).collect()
|
2015-04-10 16:50:32 -04:00
|
|
|
samples = sorted(samples, key=keyfunc)
|
2014-08-13 17:57:12 -04:00
|
|
|
|
|
|
|
# we have numPartitions many parts but one of the them has
|
|
|
|
# an implicit boundary
|
2015-04-16 19:20:57 -04:00
|
|
|
bounds = [samples[int(len(samples) * (i + 1) / numPartitions)]
|
2014-08-13 17:57:12 -04:00
|
|
|
for i in range(0, numPartitions - 1)]
|
2013-10-07 13:42:39 -04:00
|
|
|
|
2014-08-20 01:43:49 -04:00
|
|
|
def rangePartitioner(k):
|
2014-08-13 17:57:12 -04:00
|
|
|
p = bisect.bisect_left(bounds, keyfunc(k))
|
2013-10-07 13:42:39 -04:00
|
|
|
if ascending:
|
|
|
|
return p
|
|
|
|
else:
|
2014-07-14 03:42:59 -04:00
|
|
|
return numPartitions - 1 - p
|
2013-10-07 13:42:39 -04:00
|
|
|
|
2014-08-20 01:43:49 -04:00
|
|
|
return self.partitionBy(numPartitions, rangePartitioner).mapPartitions(sortPartition, True)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-06-17 14:47:48 -04:00
|
|
|
def sortBy(self, keyfunc, ascending=True, numPartitions=None):
|
|
|
|
"""
|
|
|
|
Sorts this RDD by the given keyfunc
|
|
|
|
|
|
|
|
>>> tmp = [('a', 1), ('b', 2), ('1', 3), ('d', 4), ('2', 5)]
|
|
|
|
>>> sc.parallelize(tmp).sortBy(lambda x: x[0]).collect()
|
|
|
|
[('1', 3), ('2', 5), ('a', 1), ('b', 2), ('d', 4)]
|
|
|
|
>>> sc.parallelize(tmp).sortBy(lambda x: x[1]).collect()
|
|
|
|
[('a', 1), ('b', 2), ('1', 3), ('d', 4), ('2', 5)]
|
|
|
|
"""
|
|
|
|
return self.keyBy(keyfunc).sortByKey(ascending, numPartitions).values()
|
|
|
|
|
2012-08-25 01:51:45 -04:00
|
|
|
def glom(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return an RDD created by coalescing all elements within each partition
|
|
|
|
into a list.
|
|
|
|
|
2012-08-25 01:51:45 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4], 2)
|
2012-12-29 01:19:12 -05:00
|
|
|
>>> sorted(rdd.glom().collect())
|
|
|
|
[[1, 2], [3, 4]]
|
2012-08-25 01:51:45 -04:00
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
def func(iterator):
|
|
|
|
yield list(iterator)
|
2012-08-25 17:19:07 -04:00
|
|
|
return self.mapPartitions(func)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
def cartesian(self, other):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the Cartesian product of this RDD and another one, that is, the
|
|
|
|
RDD of all pairs of elements C{(a, b)} where C{a} is in C{self} and
|
|
|
|
C{b} is in C{other}.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 2])
|
|
|
|
>>> sorted(rdd.cartesian(rdd).collect())
|
|
|
|
[(1, 1), (1, 2), (2, 1), (2, 2)]
|
|
|
|
"""
|
2012-12-29 18:34:57 -05:00
|
|
|
# Due to batching, we can't use the Java cartesian method.
|
2013-11-05 20:52:39 -05:00
|
|
|
deserializer = CartesianDeserializer(self._jrdd_deserializer,
|
|
|
|
other._jrdd_deserializer)
|
|
|
|
return RDD(self._jrdd.cartesian(other._jrdd), self.ctx, deserializer)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2013-02-24 16:25:09 -05:00
|
|
|
def groupBy(self, f, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return an RDD of grouped items.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 1, 2, 3, 5, 8])
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> result = rdd.groupBy(lambda x: x % 2).collect()
|
|
|
|
>>> sorted([(x, sorted(y)) for (x, y) in result])
|
2012-08-10 04:10:02 -04:00
|
|
|
[(0, [2, 8]), (1, [1, 1, 3, 5])]
|
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
return self.map(lambda x: (f(x), x)).groupByKey(numPartitions)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
@ignore_unicode_prefix
|
2012-08-25 21:00:25 -04:00
|
|
|
def pipe(self, command, env={}):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return an RDD created by piping elements to a forked external process.
|
|
|
|
|
2014-04-29 21:06:45 -04:00
|
|
|
>>> sc.parallelize(['1', '2', '', '3']).pipe('cat').collect()
|
2015-04-16 19:20:57 -04:00
|
|
|
[u'1', u'2', u'', u'3']
|
2012-08-25 21:00:25 -04:00
|
|
|
"""
|
|
|
|
def func(iterator):
|
2014-07-14 03:42:59 -04:00
|
|
|
pipe = Popen(
|
|
|
|
shlex.split(command), env=env, stdin=PIPE, stdout=PIPE)
|
|
|
|
|
2012-08-25 21:00:25 -04:00
|
|
|
def pipe_objs(out):
|
|
|
|
for obj in iterator:
|
2015-04-16 19:20:57 -04:00
|
|
|
s = str(obj).rstrip('\n') + '\n'
|
|
|
|
out.write(s.encode('utf-8'))
|
2012-08-25 21:00:25 -04:00
|
|
|
out.close()
|
|
|
|
Thread(target=pipe_objs, args=[pipe.stdin]).start()
|
2015-04-16 19:20:57 -04:00
|
|
|
return (x.rstrip(b'\n').decode('utf-8') for x in iter(pipe.stdout.readline, b''))
|
2012-08-25 21:00:25 -04:00
|
|
|
return self.mapPartitions(func)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
def foreach(self, f):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Applies a function to all elements of this RDD.
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> def f(x): print(x)
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> sc.parallelize([1, 2, 3, 4, 5]).foreach(f)
|
|
|
|
"""
|
2013-07-28 23:38:56 -04:00
|
|
|
def processPartition(iterator):
|
|
|
|
for x in iterator:
|
|
|
|
f(x)
|
2014-08-27 16:18:33 -04:00
|
|
|
return iter([])
|
|
|
|
self.mapPartitions(processPartition).count() # Force evaluation
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
def foreachPartition(self, f):
|
|
|
|
"""
|
|
|
|
Applies a function to each partition of this RDD.
|
|
|
|
|
2014-06-09 03:08:40 -04:00
|
|
|
>>> def f(iterator):
|
|
|
|
... for x in iterator:
|
2015-04-16 19:20:57 -04:00
|
|
|
... print(x)
|
2014-02-06 17:58:35 -05:00
|
|
|
>>> sc.parallelize([1, 2, 3, 4, 5]).foreachPartition(f)
|
|
|
|
"""
|
2014-08-27 16:18:33 -04:00
|
|
|
def func(it):
|
|
|
|
r = f(it)
|
|
|
|
try:
|
|
|
|
return iter(r)
|
|
|
|
except TypeError:
|
|
|
|
return iter([])
|
|
|
|
self.mapPartitions(func).count() # Force evaluation
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
def collect(self):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
|
|
|
Return a list that contains all of the elements in this RDD.
|
|
|
|
"""
|
2014-09-15 22:28:17 -04:00
|
|
|
with SCCallSiteSync(self.context) as css:
|
2015-03-09 19:24:06 -04:00
|
|
|
port = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
|
|
|
|
return list(_load_from_socket(port, self._jrdd_deserializer))
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
def reduce(self, f):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
Reduces the elements of this RDD using the specified commutative and
|
2014-04-25 02:07:54 -04:00
|
|
|
associative binary operator. Currently reduces partitions locally.
|
2012-12-27 20:55:33 -05:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> from operator import add
|
|
|
|
>>> sc.parallelize([1, 2, 3, 4, 5]).reduce(add)
|
2012-08-10 04:10:02 -04:00
|
|
|
15
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> sc.parallelize((2 for _ in range(10))).map(lambda x: 1).cache().reduce(add)
|
|
|
|
10
|
2014-08-27 16:18:33 -04:00
|
|
|
>>> sc.parallelize([]).reduce(add)
|
|
|
|
Traceback (most recent call last):
|
|
|
|
...
|
|
|
|
ValueError: Can not reduce() empty RDD
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-08-24 22:38:50 -04:00
|
|
|
def func(iterator):
|
2014-08-27 16:18:33 -04:00
|
|
|
iterator = iter(iterator)
|
|
|
|
try:
|
|
|
|
initial = next(iterator)
|
|
|
|
except StopIteration:
|
|
|
|
return
|
|
|
|
yield reduce(f, iterator, initial)
|
|
|
|
|
2012-08-25 17:19:07 -04:00
|
|
|
vals = self.mapPartitions(func).collect()
|
2014-08-27 16:18:33 -04:00
|
|
|
if vals:
|
|
|
|
return reduce(f, vals)
|
|
|
|
raise ValueError("Can not reduce() empty RDD")
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2015-01-28 20:26:03 -05:00
|
|
|
def treeReduce(self, f, depth=2):
|
|
|
|
"""
|
|
|
|
Reduces the elements of this RDD in a multi-level tree pattern.
|
|
|
|
|
|
|
|
:param depth: suggested depth of the tree (default: 2)
|
|
|
|
|
|
|
|
>>> add = lambda x, y: x + y
|
|
|
|
>>> rdd = sc.parallelize([-5, -4, -3, -2, -1, 1, 2, 3, 4], 10)
|
|
|
|
>>> rdd.treeReduce(add)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeReduce(add, 1)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeReduce(add, 2)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeReduce(add, 5)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeReduce(add, 10)
|
|
|
|
-5
|
|
|
|
"""
|
|
|
|
if depth < 1:
|
|
|
|
raise ValueError("Depth cannot be smaller than 1 but got %d." % depth)
|
|
|
|
|
|
|
|
zeroValue = None, True # Use the second entry to indicate whether this is a dummy value.
|
|
|
|
|
|
|
|
def op(x, y):
|
|
|
|
if x[1]:
|
|
|
|
return y
|
|
|
|
elif y[1]:
|
|
|
|
return x
|
|
|
|
else:
|
|
|
|
return f(x[0], y[0]), False
|
|
|
|
|
|
|
|
reduced = self.map(lambda x: (x, False)).treeAggregate(zeroValue, op, op, depth)
|
|
|
|
if reduced[1]:
|
|
|
|
raise ValueError("Cannot reduce empty RDD.")
|
|
|
|
return reduced[0]
|
|
|
|
|
2012-08-25 00:07:26 -04:00
|
|
|
def fold(self, zeroValue, op):
|
|
|
|
"""
|
|
|
|
Aggregate the elements of each partition, and then the results for all
|
|
|
|
the partitions, using a given associative function and a neutral "zero
|
2012-12-27 20:55:33 -05:00
|
|
|
value."
|
|
|
|
|
|
|
|
The function C{op(t1, t2)} is allowed to modify C{t1} and return it
|
2012-08-25 00:07:26 -04:00
|
|
|
as its result value to avoid object allocation; however, it should not
|
2012-12-27 20:55:33 -05:00
|
|
|
modify C{t2}.
|
2012-08-25 00:07:26 -04:00
|
|
|
|
|
|
|
>>> from operator import add
|
|
|
|
>>> sc.parallelize([1, 2, 3, 4, 5]).fold(0, add)
|
|
|
|
15
|
|
|
|
"""
|
|
|
|
def func(iterator):
|
|
|
|
acc = zeroValue
|
|
|
|
for obj in iterator:
|
|
|
|
acc = op(obj, acc)
|
|
|
|
yield acc
|
2012-08-25 17:19:07 -04:00
|
|
|
vals = self.mapPartitions(func).collect()
|
2012-08-25 00:07:26 -04:00
|
|
|
return reduce(op, vals, zeroValue)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-04-25 02:07:54 -04:00
|
|
|
def aggregate(self, zeroValue, seqOp, combOp):
|
|
|
|
"""
|
|
|
|
Aggregate the elements of each partition, and then the results for all
|
|
|
|
the partitions, using a given combine functions and a neutral "zero
|
|
|
|
value."
|
|
|
|
|
|
|
|
The functions C{op(t1, t2)} is allowed to modify C{t1} and return it
|
|
|
|
as its result value to avoid object allocation; however, it should not
|
|
|
|
modify C{t2}.
|
|
|
|
|
|
|
|
The first function (seqOp) can return a different result type, U, than
|
2014-06-12 22:44:27 -04:00
|
|
|
the type of this RDD. Thus, we need one operation for merging a T into
|
|
|
|
an U and one operation for merging two U
|
2014-04-25 02:07:54 -04:00
|
|
|
|
|
|
|
>>> seqOp = (lambda x, y: (x[0] + y, x[1] + 1))
|
|
|
|
>>> combOp = (lambda x, y: (x[0] + y[0], x[1] + y[1]))
|
|
|
|
>>> sc.parallelize([1, 2, 3, 4]).aggregate((0, 0), seqOp, combOp)
|
|
|
|
(10, 4)
|
|
|
|
>>> sc.parallelize([]).aggregate((0, 0), seqOp, combOp)
|
|
|
|
(0, 0)
|
|
|
|
"""
|
|
|
|
def func(iterator):
|
|
|
|
acc = zeroValue
|
|
|
|
for obj in iterator:
|
|
|
|
acc = seqOp(acc, obj)
|
|
|
|
yield acc
|
|
|
|
|
|
|
|
return self.mapPartitions(func).fold(zeroValue, combOp)
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2015-01-28 20:26:03 -05:00
|
|
|
def treeAggregate(self, zeroValue, seqOp, combOp, depth=2):
|
|
|
|
"""
|
|
|
|
Aggregates the elements of this RDD in a multi-level tree
|
|
|
|
pattern.
|
|
|
|
|
|
|
|
:param depth: suggested depth of the tree (default: 2)
|
|
|
|
|
|
|
|
>>> add = lambda x, y: x + y
|
|
|
|
>>> rdd = sc.parallelize([-5, -4, -3, -2, -1, 1, 2, 3, 4], 10)
|
|
|
|
>>> rdd.treeAggregate(0, add, add)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeAggregate(0, add, add, 1)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeAggregate(0, add, add, 2)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeAggregate(0, add, add, 5)
|
|
|
|
-5
|
|
|
|
>>> rdd.treeAggregate(0, add, add, 10)
|
|
|
|
-5
|
|
|
|
"""
|
|
|
|
if depth < 1:
|
|
|
|
raise ValueError("Depth cannot be smaller than 1 but got %d." % depth)
|
|
|
|
|
|
|
|
if self.getNumPartitions() == 0:
|
|
|
|
return zeroValue
|
|
|
|
|
|
|
|
def aggregatePartition(iterator):
|
|
|
|
acc = zeroValue
|
|
|
|
for obj in iterator:
|
|
|
|
acc = seqOp(acc, obj)
|
|
|
|
yield acc
|
|
|
|
|
|
|
|
partiallyAggregated = self.mapPartitions(aggregatePartition)
|
|
|
|
numPartitions = partiallyAggregated.getNumPartitions()
|
|
|
|
scale = max(int(ceil(pow(numPartitions, 1.0 / depth))), 2)
|
|
|
|
# If creating an extra level doesn't help reduce the wall-clock time, we stop the tree
|
|
|
|
# aggregation.
|
|
|
|
while numPartitions > scale + numPartitions / scale:
|
|
|
|
numPartitions /= scale
|
2015-04-16 19:20:57 -04:00
|
|
|
curNumPartitions = int(numPartitions)
|
2015-01-28 20:26:03 -05:00
|
|
|
|
|
|
|
def mapPartition(i, iterator):
|
|
|
|
for obj in iterator:
|
|
|
|
yield (i % curNumPartitions, obj)
|
|
|
|
|
|
|
|
partiallyAggregated = partiallyAggregated \
|
|
|
|
.mapPartitionsWithIndex(mapPartition) \
|
|
|
|
.reduceByKey(combOp, curNumPartitions) \
|
|
|
|
.values()
|
|
|
|
|
|
|
|
return partiallyAggregated.reduce(combOp)
|
|
|
|
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
def max(self, key=None):
|
2014-03-18 03:45:47 -04:00
|
|
|
"""
|
|
|
|
Find the maximum item in this RDD.
|
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param key: A function used to generate key for comparing
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
|
|
|
|
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
|
|
|
|
>>> rdd.max()
|
2014-03-18 03:45:47 -04:00
|
|
|
43.0
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
>>> rdd.max(key=str)
|
|
|
|
5.0
|
2014-03-18 03:45:47 -04:00
|
|
|
"""
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
if key is None:
|
|
|
|
return self.reduce(max)
|
|
|
|
return self.reduce(lambda a, b: max(a, b, key=key))
|
2014-03-18 03:45:47 -04:00
|
|
|
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
def min(self, key=None):
|
2014-03-18 03:45:47 -04:00
|
|
|
"""
|
2014-06-12 11:10:51 -04:00
|
|
|
Find the minimum item in this RDD.
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param key: A function used to generate key for comparing
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
|
|
|
|
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
|
|
|
|
>>> rdd.min()
|
|
|
|
2.0
|
|
|
|
>>> rdd.min(key=str)
|
|
|
|
10.0
|
2014-03-18 03:45:47 -04:00
|
|
|
"""
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
if key is None:
|
|
|
|
return self.reduce(min)
|
|
|
|
return self.reduce(lambda a, b: min(a, b, key=key))
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2012-12-26 20:34:24 -05:00
|
|
|
def sum(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Add up the elements in this RDD.
|
|
|
|
|
2012-12-26 20:34:24 -05:00
|
|
|
>>> sc.parallelize([1.0, 2.0, 3.0]).sum()
|
|
|
|
6.0
|
|
|
|
"""
|
|
|
|
return self.mapPartitions(lambda x: [sum(x)]).reduce(operator.add)
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
def count(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the number of elements in this RDD.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> sc.parallelize([2, 3, 4]).count()
|
2012-12-26 20:34:24 -05:00
|
|
|
3
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-26 20:34:24 -05:00
|
|
|
return self.mapPartitions(lambda i: [sum(1 for _ in i)]).sum()
|
2013-10-09 15:08:04 -04:00
|
|
|
|
2013-08-20 16:22:06 -04:00
|
|
|
def stats(self):
|
|
|
|
"""
|
|
|
|
Return a L{StatCounter} object that captures the mean, variance
|
|
|
|
and count of the RDD's elements in one operation.
|
|
|
|
"""
|
|
|
|
def redFunc(left_counter, right_counter):
|
|
|
|
return left_counter.mergeStats(right_counter)
|
|
|
|
|
|
|
|
return self.mapPartitions(lambda i: [StatCounter(i)]).reduce(redFunc)
|
|
|
|
|
[SPARK-2871] [PySpark] add histgram() API
RDD.histogram(buckets)
Compute a histogram using the provided buckets. The buckets
are all open to the right except for the last which is closed.
e.g. [1,10,20,50] means the buckets are [1,10) [10,20) [20,50],
which means 1<=x<10, 10<=x<20, 20<=x<=50. And on the input of 1
and 50 we would have a histogram of 1,0,1.
If your histogram is evenly spaced (e.g. [0, 10, 20, 30]),
this can be switched from an O(log n) inseration to O(1) per
element(where n = # buckets).
Buckets must be sorted and not contain any duplicates, must be
at least two elements.
If `buckets` is a number, it will generates buckets which is
evenly spaced between the minimum and maximum of the RDD. For
example, if the min value is 0 and the max is 100, given buckets
as 2, the resulting buckets will be [0,50) [50,100]. buckets must
be at least 1 If the RDD contains infinity, NaN throws an exception
If the elements in RDD do not vary (max == min) always returns
a single bucket.
It will return an tuple of buckets and histogram.
>>> rdd = sc.parallelize(range(51))
>>> rdd.histogram(2)
([0, 25, 50], [25, 26])
>>> rdd.histogram([0, 5, 25, 50])
([0, 5, 25, 50], [5, 20, 26])
>>> rdd.histogram([0, 15, 30, 45, 60], True)
([0, 15, 30, 45, 60], [15, 15, 15, 6])
>>> rdd = sc.parallelize(["ab", "ac", "b", "bd", "ef"])
>>> rdd.histogram(("a", "b", "c"))
(('a', 'b', 'c'), [2, 2])
closes #122, it's duplicated.
Author: Davies Liu <davies.liu@gmail.com>
Closes #2091 from davies/histgram and squashes the following commits:
a322f8a [Davies Liu] fix deprecation of e.message
84e85fa [Davies Liu] remove evenBuckets, add more tests (including str)
d9a0722 [Davies Liu] address comments
0e18a2d [Davies Liu] add histgram() API
2014-08-26 16:04:30 -04:00
|
|
|
def histogram(self, buckets):
|
|
|
|
"""
|
|
|
|
Compute a histogram using the provided buckets. The buckets
|
|
|
|
are all open to the right except for the last which is closed.
|
|
|
|
e.g. [1,10,20,50] means the buckets are [1,10) [10,20) [20,50],
|
|
|
|
which means 1<=x<10, 10<=x<20, 20<=x<=50. And on the input of 1
|
|
|
|
and 50 we would have a histogram of 1,0,1.
|
|
|
|
|
|
|
|
If your histogram is evenly spaced (e.g. [0, 10, 20, 30]),
|
|
|
|
this can be switched from an O(log n) inseration to O(1) per
|
|
|
|
element(where n = # buckets).
|
|
|
|
|
|
|
|
Buckets must be sorted and not contain any duplicates, must be
|
|
|
|
at least two elements.
|
|
|
|
|
|
|
|
If `buckets` is a number, it will generates buckets which are
|
|
|
|
evenly spaced between the minimum and maximum of the RDD. For
|
|
|
|
example, if the min value is 0 and the max is 100, given buckets
|
|
|
|
as 2, the resulting buckets will be [0,50) [50,100]. buckets must
|
|
|
|
be at least 1 If the RDD contains infinity, NaN throws an exception
|
|
|
|
If the elements in RDD do not vary (max == min) always returns
|
|
|
|
a single bucket.
|
|
|
|
|
|
|
|
It will return an tuple of buckets and histogram.
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize(range(51))
|
|
|
|
>>> rdd.histogram(2)
|
|
|
|
([0, 25, 50], [25, 26])
|
|
|
|
>>> rdd.histogram([0, 5, 25, 50])
|
|
|
|
([0, 5, 25, 50], [5, 20, 26])
|
|
|
|
>>> rdd.histogram([0, 15, 30, 45, 60]) # evenly spaced buckets
|
|
|
|
([0, 15, 30, 45, 60], [15, 15, 15, 6])
|
|
|
|
>>> rdd = sc.parallelize(["ab", "ac", "b", "bd", "ef"])
|
|
|
|
>>> rdd.histogram(("a", "b", "c"))
|
|
|
|
(('a', 'b', 'c'), [2, 2])
|
|
|
|
"""
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
if isinstance(buckets, int):
|
[SPARK-2871] [PySpark] add histgram() API
RDD.histogram(buckets)
Compute a histogram using the provided buckets. The buckets
are all open to the right except for the last which is closed.
e.g. [1,10,20,50] means the buckets are [1,10) [10,20) [20,50],
which means 1<=x<10, 10<=x<20, 20<=x<=50. And on the input of 1
and 50 we would have a histogram of 1,0,1.
If your histogram is evenly spaced (e.g. [0, 10, 20, 30]),
this can be switched from an O(log n) inseration to O(1) per
element(where n = # buckets).
Buckets must be sorted and not contain any duplicates, must be
at least two elements.
If `buckets` is a number, it will generates buckets which is
evenly spaced between the minimum and maximum of the RDD. For
example, if the min value is 0 and the max is 100, given buckets
as 2, the resulting buckets will be [0,50) [50,100]. buckets must
be at least 1 If the RDD contains infinity, NaN throws an exception
If the elements in RDD do not vary (max == min) always returns
a single bucket.
It will return an tuple of buckets and histogram.
>>> rdd = sc.parallelize(range(51))
>>> rdd.histogram(2)
([0, 25, 50], [25, 26])
>>> rdd.histogram([0, 5, 25, 50])
([0, 5, 25, 50], [5, 20, 26])
>>> rdd.histogram([0, 15, 30, 45, 60], True)
([0, 15, 30, 45, 60], [15, 15, 15, 6])
>>> rdd = sc.parallelize(["ab", "ac", "b", "bd", "ef"])
>>> rdd.histogram(("a", "b", "c"))
(('a', 'b', 'c'), [2, 2])
closes #122, it's duplicated.
Author: Davies Liu <davies.liu@gmail.com>
Closes #2091 from davies/histgram and squashes the following commits:
a322f8a [Davies Liu] fix deprecation of e.message
84e85fa [Davies Liu] remove evenBuckets, add more tests (including str)
d9a0722 [Davies Liu] address comments
0e18a2d [Davies Liu] add histgram() API
2014-08-26 16:04:30 -04:00
|
|
|
if buckets < 1:
|
|
|
|
raise ValueError("number of buckets must be >= 1")
|
|
|
|
|
|
|
|
# filter out non-comparable elements
|
|
|
|
def comparable(x):
|
|
|
|
if x is None:
|
|
|
|
return False
|
|
|
|
if type(x) is float and isnan(x):
|
|
|
|
return False
|
|
|
|
return True
|
|
|
|
|
|
|
|
filtered = self.filter(comparable)
|
|
|
|
|
|
|
|
# faster than stats()
|
|
|
|
def minmax(a, b):
|
|
|
|
return min(a[0], b[0]), max(a[1], b[1])
|
|
|
|
try:
|
|
|
|
minv, maxv = filtered.map(lambda x: (x, x)).reduce(minmax)
|
|
|
|
except TypeError as e:
|
|
|
|
if " empty " in str(e):
|
|
|
|
raise ValueError("can not generate buckets from empty RDD")
|
|
|
|
raise
|
|
|
|
|
|
|
|
if minv == maxv or buckets == 1:
|
|
|
|
return [minv, maxv], [filtered.count()]
|
|
|
|
|
|
|
|
try:
|
|
|
|
inc = (maxv - minv) / buckets
|
|
|
|
except TypeError:
|
|
|
|
raise TypeError("Can not generate buckets with non-number in RDD")
|
|
|
|
|
|
|
|
if isinf(inc):
|
|
|
|
raise ValueError("Can not generate buckets with infinite value")
|
|
|
|
|
|
|
|
# keep them as integer if possible
|
2015-04-16 19:20:57 -04:00
|
|
|
inc = int(inc)
|
[SPARK-2871] [PySpark] add histgram() API
RDD.histogram(buckets)
Compute a histogram using the provided buckets. The buckets
are all open to the right except for the last which is closed.
e.g. [1,10,20,50] means the buckets are [1,10) [10,20) [20,50],
which means 1<=x<10, 10<=x<20, 20<=x<=50. And on the input of 1
and 50 we would have a histogram of 1,0,1.
If your histogram is evenly spaced (e.g. [0, 10, 20, 30]),
this can be switched from an O(log n) inseration to O(1) per
element(where n = # buckets).
Buckets must be sorted and not contain any duplicates, must be
at least two elements.
If `buckets` is a number, it will generates buckets which is
evenly spaced between the minimum and maximum of the RDD. For
example, if the min value is 0 and the max is 100, given buckets
as 2, the resulting buckets will be [0,50) [50,100]. buckets must
be at least 1 If the RDD contains infinity, NaN throws an exception
If the elements in RDD do not vary (max == min) always returns
a single bucket.
It will return an tuple of buckets and histogram.
>>> rdd = sc.parallelize(range(51))
>>> rdd.histogram(2)
([0, 25, 50], [25, 26])
>>> rdd.histogram([0, 5, 25, 50])
([0, 5, 25, 50], [5, 20, 26])
>>> rdd.histogram([0, 15, 30, 45, 60], True)
([0, 15, 30, 45, 60], [15, 15, 15, 6])
>>> rdd = sc.parallelize(["ab", "ac", "b", "bd", "ef"])
>>> rdd.histogram(("a", "b", "c"))
(('a', 'b', 'c'), [2, 2])
closes #122, it's duplicated.
Author: Davies Liu <davies.liu@gmail.com>
Closes #2091 from davies/histgram and squashes the following commits:
a322f8a [Davies Liu] fix deprecation of e.message
84e85fa [Davies Liu] remove evenBuckets, add more tests (including str)
d9a0722 [Davies Liu] address comments
0e18a2d [Davies Liu] add histgram() API
2014-08-26 16:04:30 -04:00
|
|
|
if inc * buckets != maxv - minv:
|
|
|
|
inc = (maxv - minv) * 1.0 / buckets
|
|
|
|
|
|
|
|
buckets = [i * inc + minv for i in range(buckets)]
|
|
|
|
buckets.append(maxv) # fix accumulated error
|
|
|
|
even = True
|
|
|
|
|
|
|
|
elif isinstance(buckets, (list, tuple)):
|
|
|
|
if len(buckets) < 2:
|
|
|
|
raise ValueError("buckets should have more than one value")
|
|
|
|
|
|
|
|
if any(i is None or isinstance(i, float) and isnan(i) for i in buckets):
|
|
|
|
raise ValueError("can not have None or NaN in buckets")
|
|
|
|
|
|
|
|
if sorted(buckets) != list(buckets):
|
|
|
|
raise ValueError("buckets should be sorted")
|
|
|
|
|
|
|
|
if len(set(buckets)) != len(buckets):
|
|
|
|
raise ValueError("buckets should not contain duplicated values")
|
|
|
|
|
|
|
|
minv = buckets[0]
|
|
|
|
maxv = buckets[-1]
|
|
|
|
even = False
|
|
|
|
inc = None
|
|
|
|
try:
|
|
|
|
steps = [buckets[i + 1] - buckets[i] for i in range(len(buckets) - 1)]
|
|
|
|
except TypeError:
|
|
|
|
pass # objects in buckets do not support '-'
|
|
|
|
else:
|
|
|
|
if max(steps) - min(steps) < 1e-10: # handle precision errors
|
|
|
|
even = True
|
|
|
|
inc = (maxv - minv) / (len(buckets) - 1)
|
|
|
|
|
|
|
|
else:
|
|
|
|
raise TypeError("buckets should be a list or tuple or number(int or long)")
|
|
|
|
|
|
|
|
def histogram(iterator):
|
|
|
|
counters = [0] * len(buckets)
|
|
|
|
for i in iterator:
|
|
|
|
if i is None or (type(i) is float and isnan(i)) or i > maxv or i < minv:
|
|
|
|
continue
|
|
|
|
t = (int((i - minv) / inc) if even
|
|
|
|
else bisect.bisect_right(buckets, i) - 1)
|
|
|
|
counters[t] += 1
|
|
|
|
# add last two together
|
|
|
|
last = counters.pop()
|
|
|
|
counters[-1] += last
|
|
|
|
return [counters]
|
|
|
|
|
|
|
|
def mergeCounters(a, b):
|
|
|
|
return [i + j for i, j in zip(a, b)]
|
|
|
|
|
|
|
|
return buckets, self.mapPartitions(histogram).reduce(mergeCounters)
|
|
|
|
|
2013-08-20 16:22:06 -04:00
|
|
|
def mean(self):
|
|
|
|
"""
|
|
|
|
Compute the mean of this RDD's elements.
|
|
|
|
|
|
|
|
>>> sc.parallelize([1, 2, 3]).mean()
|
|
|
|
2.0
|
|
|
|
"""
|
|
|
|
return self.stats().mean()
|
|
|
|
|
|
|
|
def variance(self):
|
|
|
|
"""
|
|
|
|
Compute the variance of this RDD's elements.
|
|
|
|
|
|
|
|
>>> sc.parallelize([1, 2, 3]).variance()
|
|
|
|
0.666...
|
|
|
|
"""
|
|
|
|
return self.stats().variance()
|
|
|
|
|
|
|
|
def stdev(self):
|
|
|
|
"""
|
|
|
|
Compute the standard deviation of this RDD's elements.
|
|
|
|
|
|
|
|
>>> sc.parallelize([1, 2, 3]).stdev()
|
|
|
|
0.816...
|
|
|
|
"""
|
|
|
|
return self.stats().stdev()
|
2013-10-09 15:08:04 -04:00
|
|
|
|
2013-08-20 16:22:06 -04:00
|
|
|
def sampleStdev(self):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Compute the sample standard deviation of this RDD's elements (which
|
|
|
|
corrects for bias in estimating the standard deviation by dividing by
|
|
|
|
N-1 instead of N).
|
2013-08-20 16:22:06 -04:00
|
|
|
|
|
|
|
>>> sc.parallelize([1, 2, 3]).sampleStdev()
|
|
|
|
1.0
|
|
|
|
"""
|
|
|
|
return self.stats().sampleStdev()
|
|
|
|
|
|
|
|
def sampleVariance(self):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Compute the sample variance of this RDD's elements (which corrects
|
|
|
|
for bias in estimating the variance by dividing by N-1 instead of N).
|
2013-08-20 16:22:06 -04:00
|
|
|
|
|
|
|
>>> sc.parallelize([1, 2, 3]).sampleVariance()
|
|
|
|
1.0
|
|
|
|
"""
|
|
|
|
return self.stats().sampleVariance()
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-25 01:51:45 -04:00
|
|
|
def countByValue(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the count of each unique value in this RDD as a dictionary of
|
|
|
|
(value, count) pairs.
|
|
|
|
|
2012-09-17 03:08:50 -04:00
|
|
|
>>> sorted(sc.parallelize([1, 2, 1, 2, 2], 2).countByValue().items())
|
|
|
|
[(1, 2), (2, 3)]
|
2012-08-25 01:51:45 -04:00
|
|
|
"""
|
|
|
|
def countPartition(iterator):
|
2012-09-17 03:08:50 -04:00
|
|
|
counts = defaultdict(int)
|
|
|
|
for obj in iterator:
|
|
|
|
counts[obj] += 1
|
|
|
|
yield counts
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2012-08-25 01:51:45 -04:00
|
|
|
def mergeMaps(m1, m2):
|
2015-04-16 19:20:57 -04:00
|
|
|
for k, v in m2.items():
|
2012-09-17 03:08:50 -04:00
|
|
|
m1[k] += v
|
|
|
|
return m1
|
2012-08-25 01:51:45 -04:00
|
|
|
return self.mapPartitions(countPartition).reduce(mergeMaps)
|
2014-06-09 03:08:40 -04:00
|
|
|
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
def top(self, num, key=None):
|
2014-03-12 18:57:44 -04:00
|
|
|
"""
|
|
|
|
Get the top N elements from a RDD.
|
|
|
|
|
2014-03-26 12:16:37 -04:00
|
|
|
Note: It returns the list sorted in descending order.
|
2014-09-12 12:46:21 -04:00
|
|
|
|
2014-03-12 18:57:44 -04:00
|
|
|
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
|
|
|
|
[12]
|
2014-06-17 15:03:22 -04:00
|
|
|
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
|
2014-03-26 12:16:37 -04:00
|
|
|
[6, 5]
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
|
|
|
|
[4, 3, 2]
|
2014-03-12 18:57:44 -04:00
|
|
|
"""
|
|
|
|
def topIterator(iterator):
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
yield heapq.nlargest(num, iterator, key=key)
|
2014-03-12 18:57:44 -04:00
|
|
|
|
|
|
|
def merge(a, b):
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
return heapq.nlargest(num, a + b, key=key)
|
2014-03-12 18:57:44 -04:00
|
|
|
|
[SPARK-2871] [PySpark] add `key` argument for max(), min() and top(n)
RDD.max(key=None)
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([1.0, 5.0, 43.0, 10.0])
>>> rdd.max()
43.0
>>> rdd.max(key=str)
5.0
RDD.min(key=None)
Find the minimum item in this RDD.
param key: A function used to generate key for comparing
>>> rdd = sc.parallelize([2.0, 5.0, 43.0, 10.0])
>>> rdd.min()
2.0
>>> rdd.min(key=str)
10.0
RDD.top(num, key=None)
Get the top N elements from a RDD.
Note: It returns the list sorted in descending order.
>>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
[12]
>>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)
[6, 5]
>>> sc.parallelize([10, 4, 2, 12, 3]).top(3, key=str)
[4, 3, 2]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2094 from davies/cmp and squashes the following commits:
ccbaf25 [Davies Liu] add `key` to top()
ad7e374 [Davies Liu] fix tests
2f63512 [Davies Liu] change `comp` to `key` in min/max
dd91e08 [Davies Liu] add `comp` argument for RDD.max() and RDD.min()
2014-08-23 21:55:13 -04:00
|
|
|
return self.mapPartitions(topIterator).reduce(merge)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-04-03 18:42:17 -04:00
|
|
|
def takeOrdered(self, num, key=None):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Get the N elements from a RDD ordered in ascending order or as
|
|
|
|
specified by the optional key function.
|
2014-04-03 18:42:17 -04:00
|
|
|
|
|
|
|
>>> sc.parallelize([10, 1, 2, 9, 3, 4, 5, 6, 7]).takeOrdered(6)
|
|
|
|
[1, 2, 3, 4, 5, 6]
|
|
|
|
>>> sc.parallelize([10, 1, 2, 9, 3, 4, 5, 6, 7], 2).takeOrdered(6, key=lambda x: -x)
|
|
|
|
[10, 9, 7, 6, 5, 4]
|
|
|
|
"""
|
|
|
|
|
|
|
|
def merge(a, b):
|
2014-08-27 16:18:33 -04:00
|
|
|
return heapq.nsmallest(num, a + b, key)
|
|
|
|
|
|
|
|
return self.mapPartitions(lambda it: [heapq.nsmallest(num, it, key)]).reduce(merge)
|
2014-04-03 18:42:17 -04:00
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
def take(self, num):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Take the first num elements of the RDD.
|
|
|
|
|
2014-05-31 16:04:57 -04:00
|
|
|
It works by first scanning one partition, and use the results from
|
|
|
|
that partition to estimate the number of additional partitions needed
|
|
|
|
to satisfy the limit.
|
|
|
|
|
|
|
|
Translated from the Scala implementation in RDD#take().
|
2012-12-27 20:55:33 -05:00
|
|
|
|
2013-01-03 17:52:21 -05:00
|
|
|
>>> sc.parallelize([2, 3, 4, 5, 6]).cache().take(2)
|
2012-08-10 04:10:02 -04:00
|
|
|
[2, 3]
|
2012-12-29 01:19:12 -05:00
|
|
|
>>> sc.parallelize([2, 3, 4, 5, 6]).take(10)
|
|
|
|
[2, 3, 4, 5, 6]
|
2014-05-31 16:04:57 -04:00
|
|
|
>>> sc.parallelize(range(100), 100).filter(lambda x: x > 90).take(3)
|
|
|
|
[91, 92, 93]
|
2012-12-29 01:19:12 -05:00
|
|
|
"""
|
|
|
|
items = []
|
2015-04-15 15:58:02 -04:00
|
|
|
totalParts = self.getNumPartitions()
|
2014-05-31 16:04:57 -04:00
|
|
|
partsScanned = 0
|
|
|
|
|
|
|
|
while len(items) < num and partsScanned < totalParts:
|
|
|
|
# The number of partitions to try in this iteration.
|
|
|
|
# It is ok for this number to be greater than totalParts because
|
|
|
|
# we actually cap it at totalParts in runJob.
|
|
|
|
numPartsToTry = 1
|
|
|
|
if partsScanned > 0:
|
2014-09-05 21:52:05 -04:00
|
|
|
# If we didn't find any rows after the previous iteration,
|
|
|
|
# quadruple and retry. Otherwise, interpolate the number of
|
|
|
|
# partitions we need to try, but overestimate it by 50%.
|
2014-10-13 16:11:55 -04:00
|
|
|
# We also cap the estimation in the end.
|
2014-05-31 16:04:57 -04:00
|
|
|
if len(items) == 0:
|
2014-09-05 21:52:05 -04:00
|
|
|
numPartsToTry = partsScanned * 4
|
2014-05-31 16:04:57 -04:00
|
|
|
else:
|
2014-10-13 16:11:55 -04:00
|
|
|
# the first paramter of max is >=1 whenever partsScanned >= 2
|
|
|
|
numPartsToTry = int(1.5 * num * partsScanned / len(items)) - partsScanned
|
|
|
|
numPartsToTry = min(max(numPartsToTry, 1), partsScanned * 4)
|
2014-05-31 16:04:57 -04:00
|
|
|
|
|
|
|
left = num - len(items)
|
|
|
|
|
|
|
|
def takeUpToNumLeft(iterator):
|
2014-08-27 16:18:33 -04:00
|
|
|
iterator = iter(iterator)
|
2014-05-31 16:04:57 -04:00
|
|
|
taken = 0
|
|
|
|
while taken < left:
|
|
|
|
yield next(iterator)
|
|
|
|
taken += 1
|
|
|
|
|
2014-08-27 16:18:33 -04:00
|
|
|
p = range(partsScanned, min(partsScanned + numPartsToTry, totalParts))
|
2014-05-31 16:04:57 -04:00
|
|
|
res = self.context.runJob(self, takeUpToNumLeft, p, True)
|
|
|
|
|
|
|
|
items += res
|
|
|
|
partsScanned += numPartsToTry
|
|
|
|
|
2012-12-29 01:19:12 -05:00
|
|
|
return items[:num]
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
def first(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the first element in this RDD.
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> sc.parallelize([2, 3, 4]).first()
|
|
|
|
2
|
2014-08-27 16:18:33 -04:00
|
|
|
>>> sc.parallelize([]).first()
|
|
|
|
Traceback (most recent call last):
|
|
|
|
...
|
|
|
|
ValueError: RDD is empty
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2014-08-27 16:18:33 -04:00
|
|
|
rs = self.take(1)
|
|
|
|
if rs:
|
|
|
|
return rs[0]
|
|
|
|
raise ValueError("RDD is empty")
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2015-01-20 01:50:44 -05:00
|
|
|
def isEmpty(self):
|
|
|
|
"""
|
|
|
|
Returns true if and only if the RDD contains no elements at all. Note that an RDD
|
|
|
|
may be empty even when it has at least 1 partition.
|
|
|
|
|
|
|
|
>>> sc.parallelize([]).isEmpty()
|
|
|
|
True
|
|
|
|
>>> sc.parallelize([1]).isEmpty()
|
|
|
|
False
|
|
|
|
"""
|
2015-04-15 15:58:02 -04:00
|
|
|
return self.getNumPartitions() == 0 or len(self.take(1)) == 0
|
2015-01-20 01:50:44 -05:00
|
|
|
|
2014-07-30 16:19:05 -04:00
|
|
|
def saveAsNewAPIHadoopDataset(self, conf, keyConverter=None, valueConverter=None):
|
|
|
|
"""
|
|
|
|
Output a Python RDD of key-value pairs (of form C{RDD[(K, V)]}) to any Hadoop file
|
|
|
|
system, using the new Hadoop OutputFormat API (mapreduce package). Keys/values are
|
|
|
|
converted for output using either user specified converters or, by default,
|
|
|
|
L{org.apache.spark.api.python.JavaToWritableConverter}.
|
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param conf: Hadoop job configuration, passed in as a dict
|
|
|
|
:param keyConverter: (None by default)
|
|
|
|
:param valueConverter: (None by default)
|
2014-07-30 16:19:05 -04:00
|
|
|
"""
|
|
|
|
jconf = self.ctx._dictToJavaMap(conf)
|
2014-11-04 02:56:14 -05:00
|
|
|
pickledRDD = self._pickled()
|
|
|
|
self.ctx._jvm.PythonRDD.saveAsHadoopDataset(pickledRDD._jrdd, True, jconf,
|
2014-07-30 16:19:05 -04:00
|
|
|
keyConverter, valueConverter, True)
|
|
|
|
|
|
|
|
def saveAsNewAPIHadoopFile(self, path, outputFormatClass, keyClass=None, valueClass=None,
|
|
|
|
keyConverter=None, valueConverter=None, conf=None):
|
|
|
|
"""
|
|
|
|
Output a Python RDD of key-value pairs (of form C{RDD[(K, V)]}) to any Hadoop file
|
|
|
|
system, using the new Hadoop OutputFormat API (mapreduce package). Key and value types
|
|
|
|
will be inferred if not specified. Keys and values are converted for output using either
|
|
|
|
user specified converters or L{org.apache.spark.api.python.JavaToWritableConverter}. The
|
|
|
|
C{conf} is applied on top of the base Hadoop conf associated with the SparkContext
|
|
|
|
of this RDD to create a merged Hadoop MapReduce job configuration for saving the data.
|
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param path: path to Hadoop file
|
|
|
|
:param outputFormatClass: fully qualified classname of Hadoop OutputFormat
|
2014-07-30 16:19:05 -04:00
|
|
|
(e.g. "org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat")
|
2014-10-07 21:09:27 -04:00
|
|
|
:param keyClass: fully qualified classname of key Writable class
|
2014-07-30 16:19:05 -04:00
|
|
|
(e.g. "org.apache.hadoop.io.IntWritable", None by default)
|
2014-10-07 21:09:27 -04:00
|
|
|
:param valueClass: fully qualified classname of value Writable class
|
2014-07-30 16:19:05 -04:00
|
|
|
(e.g. "org.apache.hadoop.io.Text", None by default)
|
2014-10-07 21:09:27 -04:00
|
|
|
:param keyConverter: (None by default)
|
|
|
|
:param valueConverter: (None by default)
|
|
|
|
:param conf: Hadoop job configuration, passed in as a dict (None by default)
|
2014-07-30 16:19:05 -04:00
|
|
|
"""
|
|
|
|
jconf = self.ctx._dictToJavaMap(conf)
|
2014-11-04 02:56:14 -05:00
|
|
|
pickledRDD = self._pickled()
|
|
|
|
self.ctx._jvm.PythonRDD.saveAsNewAPIHadoopFile(pickledRDD._jrdd, True, path,
|
2014-08-06 15:58:24 -04:00
|
|
|
outputFormatClass,
|
|
|
|
keyClass, valueClass,
|
|
|
|
keyConverter, valueConverter, jconf)
|
2014-07-30 16:19:05 -04:00
|
|
|
|
|
|
|
def saveAsHadoopDataset(self, conf, keyConverter=None, valueConverter=None):
|
|
|
|
"""
|
|
|
|
Output a Python RDD of key-value pairs (of form C{RDD[(K, V)]}) to any Hadoop file
|
|
|
|
system, using the old Hadoop OutputFormat API (mapred package). Keys/values are
|
|
|
|
converted for output using either user specified converters or, by default,
|
|
|
|
L{org.apache.spark.api.python.JavaToWritableConverter}.
|
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param conf: Hadoop job configuration, passed in as a dict
|
|
|
|
:param keyConverter: (None by default)
|
|
|
|
:param valueConverter: (None by default)
|
2014-07-30 16:19:05 -04:00
|
|
|
"""
|
|
|
|
jconf = self.ctx._dictToJavaMap(conf)
|
2014-11-04 02:56:14 -05:00
|
|
|
pickledRDD = self._pickled()
|
|
|
|
self.ctx._jvm.PythonRDD.saveAsHadoopDataset(pickledRDD._jrdd, True, jconf,
|
2014-07-30 16:19:05 -04:00
|
|
|
keyConverter, valueConverter, False)
|
|
|
|
|
|
|
|
def saveAsHadoopFile(self, path, outputFormatClass, keyClass=None, valueClass=None,
|
|
|
|
keyConverter=None, valueConverter=None, conf=None,
|
|
|
|
compressionCodecClass=None):
|
|
|
|
"""
|
|
|
|
Output a Python RDD of key-value pairs (of form C{RDD[(K, V)]}) to any Hadoop file
|
|
|
|
system, using the old Hadoop OutputFormat API (mapred package). Key and value types
|
|
|
|
will be inferred if not specified. Keys and values are converted for output using either
|
|
|
|
user specified converters or L{org.apache.spark.api.python.JavaToWritableConverter}. The
|
|
|
|
C{conf} is applied on top of the base Hadoop conf associated with the SparkContext
|
|
|
|
of this RDD to create a merged Hadoop MapReduce job configuration for saving the data.
|
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param path: path to Hadoop file
|
|
|
|
:param outputFormatClass: fully qualified classname of Hadoop OutputFormat
|
2014-07-30 16:19:05 -04:00
|
|
|
(e.g. "org.apache.hadoop.mapred.SequenceFileOutputFormat")
|
2014-10-07 21:09:27 -04:00
|
|
|
:param keyClass: fully qualified classname of key Writable class
|
2014-07-30 16:19:05 -04:00
|
|
|
(e.g. "org.apache.hadoop.io.IntWritable", None by default)
|
2014-10-07 21:09:27 -04:00
|
|
|
:param valueClass: fully qualified classname of value Writable class
|
2014-07-30 16:19:05 -04:00
|
|
|
(e.g. "org.apache.hadoop.io.Text", None by default)
|
2014-10-07 21:09:27 -04:00
|
|
|
:param keyConverter: (None by default)
|
|
|
|
:param valueConverter: (None by default)
|
|
|
|
:param conf: (None by default)
|
|
|
|
:param compressionCodecClass: (None by default)
|
2014-07-30 16:19:05 -04:00
|
|
|
"""
|
|
|
|
jconf = self.ctx._dictToJavaMap(conf)
|
2014-11-04 02:56:14 -05:00
|
|
|
pickledRDD = self._pickled()
|
|
|
|
self.ctx._jvm.PythonRDD.saveAsHadoopFile(pickledRDD._jrdd, True, path,
|
2014-08-06 15:58:24 -04:00
|
|
|
outputFormatClass,
|
|
|
|
keyClass, valueClass,
|
|
|
|
keyConverter, valueConverter,
|
|
|
|
jconf, compressionCodecClass)
|
2014-07-30 16:19:05 -04:00
|
|
|
|
|
|
|
def saveAsSequenceFile(self, path, compressionCodecClass=None):
|
|
|
|
"""
|
|
|
|
Output a Python RDD of key-value pairs (of form C{RDD[(K, V)]}) to any Hadoop file
|
|
|
|
system, using the L{org.apache.hadoop.io.Writable} types that we convert from the
|
|
|
|
RDD's key and value types. The mechanism is as follows:
|
2014-10-06 17:08:40 -04:00
|
|
|
|
2014-07-30 16:19:05 -04:00
|
|
|
1. Pyrolite is used to convert pickled Python RDD into RDD of Java objects.
|
|
|
|
2. Keys and values of this Java RDD are converted to Writables and written out.
|
|
|
|
|
2014-10-07 21:09:27 -04:00
|
|
|
:param path: path to sequence file
|
|
|
|
:param compressionCodecClass: (None by default)
|
2014-07-30 16:19:05 -04:00
|
|
|
"""
|
2014-11-04 02:56:14 -05:00
|
|
|
pickledRDD = self._pickled()
|
|
|
|
self.ctx._jvm.PythonRDD.saveAsSequenceFile(pickledRDD._jrdd, True,
|
2014-07-30 16:19:05 -04:00
|
|
|
path, compressionCodecClass)
|
|
|
|
|
2014-06-03 21:18:25 -04:00
|
|
|
def saveAsPickleFile(self, path, batchSize=10):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Save this RDD as a SequenceFile of serialized objects. The serializer
|
|
|
|
used is L{pyspark.serializers.PickleSerializer}, default batch size
|
|
|
|
is 10.
|
2014-06-03 21:18:25 -04:00
|
|
|
|
|
|
|
>>> tmpFile = NamedTemporaryFile(delete=True)
|
|
|
|
>>> tmpFile.close()
|
|
|
|
>>> sc.parallelize([1, 2, 'spark', 'rdd']).saveAsPickleFile(tmpFile.name, 3)
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> sorted(sc.pickleFile(tmpFile.name, 5).map(str).collect())
|
|
|
|
['1', '2', 'rdd', 'spark']
|
2014-06-03 21:18:25 -04:00
|
|
|
"""
|
2014-11-04 02:56:14 -05:00
|
|
|
if batchSize == 0:
|
|
|
|
ser = AutoBatchedSerializer(PickleSerializer())
|
|
|
|
else:
|
|
|
|
ser = BatchedSerializer(PickleSerializer(), batchSize)
|
|
|
|
self._reserialize(ser)._jrdd.saveAsObjectFile(path)
|
2014-06-03 21:18:25 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
@ignore_unicode_prefix
|
2015-02-06 16:55:02 -05:00
|
|
|
def saveAsTextFile(self, path, compressionCodecClass=None):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
|
|
|
Save this RDD as a text file, using string representations of elements.
|
2012-12-29 20:06:50 -05:00
|
|
|
|
2015-02-06 16:55:02 -05:00
|
|
|
@param path: path to text file
|
|
|
|
@param compressionCodecClass: (None by default) string i.e.
|
|
|
|
"org.apache.hadoop.io.compress.GzipCodec"
|
|
|
|
|
2012-12-29 20:06:50 -05:00
|
|
|
>>> tempFile = NamedTemporaryFile(delete=True)
|
|
|
|
>>> tempFile.close()
|
|
|
|
>>> sc.parallelize(range(10)).saveAsTextFile(tempFile.name)
|
|
|
|
>>> from fileinput import input
|
|
|
|
>>> from glob import glob
|
2013-04-02 14:58:40 -04:00
|
|
|
>>> ''.join(sorted(input(glob(tempFile.name + "/part-0000*"))))
|
2012-12-29 20:06:50 -05:00
|
|
|
'0\\n1\\n2\\n3\\n4\\n5\\n6\\n7\\n8\\n9\\n'
|
2014-05-10 17:01:08 -04:00
|
|
|
|
|
|
|
Empty lines are tolerated when saving to text files.
|
|
|
|
|
|
|
|
>>> tempFile2 = NamedTemporaryFile(delete=True)
|
|
|
|
>>> tempFile2.close()
|
|
|
|
>>> sc.parallelize(['', 'foo', '', 'bar', '']).saveAsTextFile(tempFile2.name)
|
|
|
|
>>> ''.join(sorted(input(glob(tempFile2.name + "/part-0000*"))))
|
|
|
|
'\\n\\n\\nbar\\nfoo\\n'
|
2015-02-06 16:55:02 -05:00
|
|
|
|
|
|
|
Using compressionCodecClass
|
|
|
|
|
|
|
|
>>> tempFile3 = NamedTemporaryFile(delete=True)
|
|
|
|
>>> tempFile3.close()
|
|
|
|
>>> codec = "org.apache.hadoop.io.compress.GzipCodec"
|
|
|
|
>>> sc.parallelize(['foo', 'bar']).saveAsTextFile(tempFile3.name, codec)
|
|
|
|
>>> from fileinput import input, hook_compressed
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> result = sorted(input(glob(tempFile3.name + "/part*.gz"), openhook=hook_compressed))
|
|
|
|
>>> b''.join(result).decode('utf-8')
|
|
|
|
u'bar\\nfoo\\n'
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2013-01-08 19:04:41 -05:00
|
|
|
def func(split, iterator):
|
2013-11-29 02:44:56 -05:00
|
|
|
for x in iterator:
|
2015-04-16 19:20:57 -04:00
|
|
|
if not isinstance(x, (unicode, bytes)):
|
2013-11-29 02:44:56 -05:00
|
|
|
x = unicode(x)
|
2014-08-18 16:58:35 -04:00
|
|
|
if isinstance(x, unicode):
|
|
|
|
x = x.encode("utf-8")
|
|
|
|
yield x
|
[SPARK-2010] [PySpark] [SQL] support nested structure in SchemaRDD
Convert Row in JavaSchemaRDD into Array[Any] and unpickle them as tuple in Python, then convert them into namedtuple, so use can access fields just like attributes.
This will let nested structure can be accessed as object, also it will reduce the size of serialized data and better performance.
root
|-- field1: integer (nullable = true)
|-- field2: string (nullable = true)
|-- field3: struct (nullable = true)
| |-- field4: integer (nullable = true)
| |-- field5: array (nullable = true)
| | |-- element: integer (containsNull = false)
|-- field6: array (nullable = true)
| |-- element: struct (containsNull = false)
| | |-- field7: string (nullable = true)
Then we can access them by row.field3.field5[0] or row.field6[5].field7
It also will infer the schema in Python, convert Row/dict/namedtuple/objects into tuple before serialization, then call applySchema in JVM. During inferSchema(), the top level of dict in row will be StructType, but any nested dictionary will be MapType.
You can use pyspark.sql.Row to convert unnamed structure into Row object, make the RDD can be inferable. Such as:
ctx.inferSchema(rdd.map(lambda x: Row(a=x[0], b=x[1]))
Or you could use Row to create a class just like namedtuple, for example:
Person = Row("name", "age")
ctx.inferSchema(rdd.map(lambda x: Person(*x)))
Also, you can call applySchema to apply an schema to a RDD of tuple/list and turn it into a SchemaRDD. The `schema` should be StructType, see the API docs for details.
schema = StructType([StructField("name, StringType, True),
StructType("age", IntegerType, True)])
ctx.applySchema(rdd, schema)
PS: In order to use namedtuple to inferSchema, you should make namedtuple picklable.
Author: Davies Liu <davies.liu@gmail.com>
Closes #1598 from davies/nested and squashes the following commits:
f1d15b6 [Davies Liu] verify schema with the first few rows
8852aaf [Davies Liu] check type of schema
abe9e6e [Davies Liu] address comments
61b2292 [Davies Liu] add @deprecated to pythonToJavaMap
1e5b801 [Davies Liu] improve cache of classes
51aa135 [Davies Liu] use Row to infer schema
e9c0d5c [Davies Liu] remove string typed schema
353a3f2 [Davies Liu] fix code style
63de8f8 [Davies Liu] fix typo
c79ca67 [Davies Liu] fix serialization of nested data
6b258b5 [Davies Liu] fix pep8
9d8447c [Davies Liu] apply schema provided by string of names
f5df97f [Davies Liu] refactor, address comments
9d9af55 [Davies Liu] use arrry to applySchema and infer schema in Python
84679b3 [Davies Liu] Merge branch 'master' of github.com:apache/spark into nested
0eaaf56 [Davies Liu] fix doc tests
b3559b4 [Davies Liu] use generated Row instead of namedtuple
c4ddc30 [Davies Liu] fix conflict between name of fields and variables
7f6f251 [Davies Liu] address all comments
d69d397 [Davies Liu] refactor
2cc2d45 [Davies Liu] refactor
182fb46 [Davies Liu] refactor
bc6e9e1 [Davies Liu] switch to new Schema API
547bf3e [Davies Liu] Merge branch 'master' into nested
a435b5a [Davies Liu] add docs and code refactor
2c8debc [Davies Liu] Merge branch 'master' into nested
644665a [Davies Liu] use tuple and namedtuple for schemardd
2014-08-01 21:47:41 -04:00
|
|
|
keyed = self.mapPartitionsWithIndex(func)
|
2012-08-25 21:00:25 -04:00
|
|
|
keyed._bypass_serializer = True
|
2015-02-06 16:55:02 -05:00
|
|
|
if compressionCodecClass:
|
|
|
|
compressionCodec = self.ctx._jvm.java.lang.Class.forName(compressionCodecClass)
|
|
|
|
keyed._jrdd.map(self.ctx._jvm.BytesToString()).saveAsTextFile(path, compressionCodec)
|
|
|
|
else:
|
|
|
|
keyed._jrdd.map(self.ctx._jvm.BytesToString()).saveAsTextFile(path)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
# Pair functions
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
def collectAsMap(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return the key-value pairs in this RDD to the master as a dictionary.
|
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> m = sc.parallelize([(1, 2), (3, 4)]).collectAsMap()
|
|
|
|
>>> m[1]
|
|
|
|
2
|
|
|
|
>>> m[3]
|
|
|
|
4
|
|
|
|
"""
|
|
|
|
return dict(self.collect())
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
def keys(self):
|
|
|
|
"""
|
|
|
|
Return an RDD with the keys of each tuple.
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
>>> m = sc.parallelize([(1, 2), (3, 4)]).keys()
|
|
|
|
>>> m.collect()
|
|
|
|
[1, 3]
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
return self.map(lambda x: x[0])
|
2014-02-06 17:58:35 -05:00
|
|
|
|
|
|
|
def values(self):
|
|
|
|
"""
|
|
|
|
Return an RDD with the values of each tuple.
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
>>> m = sc.parallelize([(1, 2), (3, 4)]).values()
|
|
|
|
>>> m.collect()
|
|
|
|
[2, 4]
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
return self.map(lambda x: x[1])
|
2014-02-06 17:58:35 -05:00
|
|
|
|
2013-02-24 16:25:09 -05:00
|
|
|
def reduceByKey(self, func, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Merge the values for each key using an associative reduce function.
|
|
|
|
|
|
|
|
This will also perform the merging locally on each mapper before
|
|
|
|
sending results to a reducer, similarly to a "combiner" in MapReduce.
|
|
|
|
|
2013-02-24 16:25:09 -05:00
|
|
|
Output will be hash-partitioned with C{numPartitions} partitions, or
|
|
|
|
the default parallelism level if C{numPartitions} is not specified.
|
2012-12-27 20:55:33 -05:00
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
>>> from operator import add
|
|
|
|
>>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)])
|
|
|
|
>>> sorted(rdd.reduceByKey(add).collect())
|
2012-08-10 04:10:02 -04:00
|
|
|
[('a', 2), ('b', 1)]
|
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
return self.combineByKey(lambda x: x, func, func, numPartitions)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
def reduceByKeyLocally(self, func):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Merge the values for each key using an associative reduce function, but
|
|
|
|
return the results immediately to the master as a dictionary.
|
|
|
|
|
|
|
|
This will also perform the merging locally on each mapper before
|
|
|
|
sending results to a reducer, similarly to a "combiner" in MapReduce.
|
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
>>> from operator import add
|
|
|
|
>>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)])
|
|
|
|
>>> sorted(rdd.reduceByKeyLocally(add).items())
|
|
|
|
[('a', 2), ('b', 1)]
|
|
|
|
"""
|
|
|
|
def reducePartition(iterator):
|
|
|
|
m = {}
|
2014-08-27 16:18:33 -04:00
|
|
|
for k, v in iterator:
|
|
|
|
m[k] = func(m[k], v) if k in m else v
|
2012-08-25 02:09:15 -04:00
|
|
|
yield m
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
def mergeMaps(m1, m2):
|
2015-04-16 19:20:57 -04:00
|
|
|
for k, v in m2.items():
|
2014-08-27 16:18:33 -04:00
|
|
|
m1[k] = func(m1[k], v) if k in m1 else v
|
2012-08-25 02:09:15 -04:00
|
|
|
return m1
|
|
|
|
return self.mapPartitions(reducePartition).reduce(mergeMaps)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
def countByKey(self):
|
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Count the number of elements for each key, and return the result to the
|
|
|
|
master as a dictionary.
|
|
|
|
|
2012-08-25 02:09:15 -04:00
|
|
|
>>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)])
|
2012-09-17 03:08:50 -04:00
|
|
|
>>> sorted(rdd.countByKey().items())
|
2012-08-25 02:09:15 -04:00
|
|
|
[('a', 2), ('b', 1)]
|
|
|
|
"""
|
|
|
|
return self.map(lambda x: x[0]).countByValue()
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2013-02-24 16:25:09 -05:00
|
|
|
def join(self, other, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return an RDD containing all pairs of elements with matching keys in
|
|
|
|
C{self} and C{other}.
|
|
|
|
|
|
|
|
Each pair of elements will be returned as a (k, (v1, v2)) tuple, where
|
|
|
|
(k, v1) is in C{self} and (k, v2) is in C{other}.
|
|
|
|
|
|
|
|
Performs a hash join across the cluster.
|
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4)])
|
|
|
|
>>> y = sc.parallelize([("a", 2), ("a", 3)])
|
|
|
|
>>> sorted(x.join(y).collect())
|
2012-08-10 04:10:02 -04:00
|
|
|
[('a', (1, 2)), ('a', (1, 3))]
|
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
return python_join(self, other, numPartitions)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2013-02-24 16:25:09 -05:00
|
|
|
def leftOuterJoin(self, other, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Perform a left outer join of C{self} and C{other}.
|
|
|
|
|
|
|
|
For each element (k, v) in C{self}, the resulting RDD will either
|
|
|
|
contain all pairs (k, (v, w)) for w in C{other}, or the pair
|
2014-09-24 23:39:09 -04:00
|
|
|
(k, (v, None)) if no elements in C{other} have key k.
|
2012-12-27 20:55:33 -05:00
|
|
|
|
|
|
|
Hash-partitions the resulting RDD into the given number of partitions.
|
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4)])
|
|
|
|
>>> y = sc.parallelize([("a", 2)])
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> sorted(x.leftOuterJoin(y).collect())
|
|
|
|
[('a', (1, 2)), ('b', (4, None))]
|
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
return python_left_outer_join(self, other, numPartitions)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2013-02-24 16:25:09 -05:00
|
|
|
def rightOuterJoin(self, other, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Perform a right outer join of C{self} and C{other}.
|
|
|
|
|
|
|
|
For each element (k, w) in C{other}, the resulting RDD will either
|
|
|
|
contain all pairs (k, (v, w)) for v in this, or the pair (k, (None, w))
|
|
|
|
if no elements in C{self} have key k.
|
|
|
|
|
|
|
|
Hash-partitions the resulting RDD into the given number of partitions.
|
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4)])
|
|
|
|
>>> y = sc.parallelize([("a", 2)])
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> sorted(y.rightOuterJoin(x).collect())
|
|
|
|
[('a', (2, 1)), ('b', (None, 4))]
|
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
return python_right_outer_join(self, other, numPartitions)
|
2012-08-18 19:07:10 -04:00
|
|
|
|
2014-09-24 23:39:09 -04:00
|
|
|
def fullOuterJoin(self, other, numPartitions=None):
|
|
|
|
"""
|
|
|
|
Perform a right outer join of C{self} and C{other}.
|
|
|
|
|
|
|
|
For each element (k, v) in C{self}, the resulting RDD will either
|
|
|
|
contain all pairs (k, (v, w)) for w in C{other}, or the pair
|
|
|
|
(k, (v, None)) if no elements in C{other} have key k.
|
|
|
|
|
|
|
|
Similarly, for each element (k, w) in C{other}, the resulting RDD will
|
|
|
|
either contain all pairs (k, (v, w)) for v in C{self}, or the pair
|
|
|
|
(k, (None, w)) if no elements in C{self} have key k.
|
|
|
|
|
|
|
|
Hash-partitions the resulting RDD into the given number of partitions.
|
|
|
|
|
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4)])
|
|
|
|
>>> y = sc.parallelize([("a", 2), ("c", 8)])
|
|
|
|
>>> sorted(x.fullOuterJoin(y).collect())
|
|
|
|
[('a', (1, 2)), ('b', (4, None)), ('c', (None, 8))]
|
|
|
|
"""
|
|
|
|
return python_full_outer_join(self, other, numPartitions)
|
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
# TODO: add option to control map-side combining
|
2014-07-21 14:59:54 -04:00
|
|
|
# portable_hash is used as default, because builtin hash of None is different
|
|
|
|
# cross machines.
|
|
|
|
def partitionBy(self, numPartitions, partitionFunc=portable_hash):
|
2012-10-29 01:30:28 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Return a copy of the RDD partitioned using the specified partitioner.
|
|
|
|
|
2012-10-29 01:30:28 -04:00
|
|
|
>>> pairs = sc.parallelize([1, 2, 3, 4, 2, 4, 1]).map(lambda x: (x, x))
|
|
|
|
>>> sets = pairs.partitionBy(2).glom().collect()
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> len(set(sets[0]).intersection(set(sets[1])))
|
|
|
|
0
|
2012-10-29 01:30:28 -04:00
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
if numPartitions is None:
|
2014-06-20 03:06:57 -04:00
|
|
|
numPartitions = self._defaultReducePartitions()
|
2015-02-17 19:54:57 -05:00
|
|
|
partitioner = Partitioner(numPartitions, partitionFunc)
|
|
|
|
if self.partitioner == partitioner:
|
|
|
|
return self
|
2014-06-03 16:31:16 -04:00
|
|
|
|
2014-07-25 01:53:47 -04:00
|
|
|
# Transferring O(n) objects to Java is too expensive.
|
|
|
|
# Instead, we'll form the hash buckets in Python,
|
|
|
|
# transferring O(numPartitions) objects to Java.
|
|
|
|
# Each object is a (splitNumber, [objects]) pair.
|
|
|
|
# In order to avoid too huge objects, the objects are
|
|
|
|
# grouped into chunks.
|
2013-11-05 20:52:39 -05:00
|
|
|
outputSerializer = self.ctx._unbatched_serializer
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2014-07-25 01:53:47 -04:00
|
|
|
limit = (_parse_memory(self.ctx._conf.get(
|
2014-08-06 15:58:24 -04:00
|
|
|
"spark.python.worker.memory", "512m")) / 2)
|
2014-07-25 01:53:47 -04:00
|
|
|
|
2013-01-08 19:04:41 -05:00
|
|
|
def add_shuffle_key(split, iterator):
|
2013-10-04 14:56:47 -04:00
|
|
|
|
2012-12-24 18:01:13 -05:00
|
|
|
buckets = defaultdict(list)
|
2014-07-25 01:53:47 -04:00
|
|
|
c, batch = 0, min(10 * numPartitions, 1000)
|
2013-10-04 14:56:47 -04:00
|
|
|
|
2014-08-27 16:18:33 -04:00
|
|
|
for k, v in iterator:
|
2013-02-24 16:25:09 -05:00
|
|
|
buckets[partitionFunc(k) % numPartitions].append((k, v))
|
2014-07-25 01:53:47 -04:00
|
|
|
c += 1
|
|
|
|
|
|
|
|
# check used memory and avg size of chunk of objects
|
|
|
|
if (c % 1000 == 0 and get_used_memory() > limit
|
|
|
|
or c > batch):
|
|
|
|
n, size = len(buckets), 0
|
2015-04-16 19:20:57 -04:00
|
|
|
for split in list(buckets.keys()):
|
2014-07-25 01:53:47 -04:00
|
|
|
yield pack_long(split)
|
|
|
|
d = outputSerializer.dumps(buckets[split])
|
|
|
|
del buckets[split]
|
|
|
|
yield d
|
|
|
|
size += len(d)
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
avg = int(size / n) >> 20
|
2014-07-25 01:53:47 -04:00
|
|
|
# let 1M < avg < 10M
|
|
|
|
if avg < 1:
|
|
|
|
batch *= 1.5
|
|
|
|
elif avg > 10:
|
2015-04-16 19:20:57 -04:00
|
|
|
batch = max(int(batch / 1.5), 1)
|
2014-07-25 01:53:47 -04:00
|
|
|
c = 0
|
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
for split, items in buckets.items():
|
2013-10-04 14:56:47 -04:00
|
|
|
yield pack_long(split)
|
2013-11-10 20:48:27 -05:00
|
|
|
yield outputSerializer.dumps(items)
|
2014-07-25 01:53:47 -04:00
|
|
|
|
2015-02-17 19:54:57 -05:00
|
|
|
keyed = self.mapPartitionsWithIndex(add_shuffle_key, preservesPartitioning=True)
|
2012-08-25 19:46:07 -04:00
|
|
|
keyed._bypass_serializer = True
|
2014-09-15 22:28:17 -04:00
|
|
|
with SCCallSiteSync(self.context) as css:
|
2014-07-14 03:42:59 -04:00
|
|
|
pairRDD = self.ctx._jvm.PairwiseRDD(
|
|
|
|
keyed._jrdd.rdd()).asJavaPairRDD()
|
2015-02-17 19:54:57 -05:00
|
|
|
jpartitioner = self.ctx._jvm.PythonPartitioner(numPartitions,
|
|
|
|
id(partitionFunc))
|
|
|
|
jrdd = self.ctx._jvm.PythonRDD.valueOfPair(pairRDD.partitionBy(jpartitioner))
|
2013-11-05 20:52:39 -05:00
|
|
|
rdd = RDD(jrdd, self.ctx, BatchedSerializer(outputSerializer))
|
2015-02-17 19:54:57 -05:00
|
|
|
rdd.partitioner = partitioner
|
2013-01-14 18:30:42 -05:00
|
|
|
return rdd
|
2012-08-18 19:07:10 -04:00
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
# TODO: add control over map-side aggregation
|
2012-08-10 04:10:02 -04:00
|
|
|
def combineByKey(self, createCombiner, mergeValue, mergeCombiners,
|
2013-02-24 16:25:09 -05:00
|
|
|
numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Generic function to combine the elements for each key using a custom
|
|
|
|
set of aggregation functions.
|
|
|
|
|
|
|
|
Turns an RDD[(K, V)] into a result of type RDD[(K, C)], for a "combined
|
|
|
|
type" C. Note that V and C can be different -- for example, one might
|
|
|
|
group an RDD of type (Int, Int) into an RDD of type (Int, List[Int]).
|
|
|
|
|
|
|
|
Users provide three functions:
|
|
|
|
|
|
|
|
- C{createCombiner}, which turns a V into a C (e.g., creates
|
|
|
|
a one-element list)
|
|
|
|
- C{mergeValue}, to merge a V into a C (e.g., adds it to the end of
|
|
|
|
a list)
|
|
|
|
- C{mergeCombiners}, to combine two C's into a single one.
|
|
|
|
|
|
|
|
In addition, users can control the partitioning of the output RDD.
|
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 1), ("a", 1)])
|
2012-08-10 04:10:02 -04:00
|
|
|
>>> def f(x): return x
|
|
|
|
>>> def add(a, b): return a + str(b)
|
|
|
|
>>> sorted(x.combineByKey(str, add, add).collect())
|
|
|
|
[('a', '11'), ('b', '1')]
|
|
|
|
"""
|
2013-02-24 16:25:09 -05:00
|
|
|
if numPartitions is None:
|
2014-06-20 03:06:57 -04:00
|
|
|
numPartitions = self._defaultReducePartitions()
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2014-07-25 01:53:47 -04:00
|
|
|
serializer = self.ctx.serializer
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
spill = self._can_spill()
|
|
|
|
memory = self._memory_limit()
|
2014-07-25 01:53:47 -04:00
|
|
|
agg = Aggregator(createCombiner, mergeValue, mergeCombiners)
|
|
|
|
|
2012-08-25 17:19:07 -04:00
|
|
|
def combineLocally(iterator):
|
2014-07-25 01:53:47 -04:00
|
|
|
merger = ExternalMerger(agg, memory * 0.9, serializer) \
|
2014-08-06 15:58:24 -04:00
|
|
|
if spill else InMemoryMerger(agg)
|
2014-07-25 01:53:47 -04:00
|
|
|
merger.mergeValues(iterator)
|
2015-04-16 19:20:57 -04:00
|
|
|
return merger.items()
|
2014-07-25 01:53:47 -04:00
|
|
|
|
2015-02-17 19:54:57 -05:00
|
|
|
locally_combined = self.mapPartitions(combineLocally, preservesPartitioning=True)
|
2013-02-24 16:25:09 -05:00
|
|
|
shuffled = locally_combined.partitionBy(numPartitions)
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2012-08-25 17:19:07 -04:00
|
|
|
def _mergeCombiners(iterator):
|
2014-07-25 01:53:47 -04:00
|
|
|
merger = ExternalMerger(agg, memory, serializer) \
|
2014-08-06 15:58:24 -04:00
|
|
|
if spill else InMemoryMerger(agg)
|
2014-07-25 01:53:47 -04:00
|
|
|
merger.mergeCombiners(iterator)
|
2015-04-16 19:20:57 -04:00
|
|
|
return merger.items()
|
2014-07-25 01:53:47 -04:00
|
|
|
|
2015-02-17 19:54:57 -05:00
|
|
|
return shuffled.mapPartitions(_mergeCombiners, preservesPartitioning=True)
|
2014-06-20 14:03:03 -04:00
|
|
|
|
2014-06-12 11:14:25 -04:00
|
|
|
def aggregateByKey(self, zeroValue, seqFunc, combFunc, numPartitions=None):
|
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
Aggregate the values of each key, using given combine functions and a neutral
|
|
|
|
"zero value". This function can return a different result type, U, than the type
|
|
|
|
of the values in this RDD, V. Thus, we need one operation for merging a V into
|
|
|
|
a U and one operation for merging two U's, The former operation is used for merging
|
|
|
|
values within a partition, and the latter is used for merging values between
|
|
|
|
partitions. To avoid memory allocation, both of these functions are
|
2014-06-12 11:14:25 -04:00
|
|
|
allowed to modify and return their first argument instead of creating a new U.
|
|
|
|
"""
|
|
|
|
def createZero():
|
2014-07-14 03:42:59 -04:00
|
|
|
return copy.deepcopy(zeroValue)
|
2014-06-20 14:03:03 -04:00
|
|
|
|
2014-07-14 03:42:59 -04:00
|
|
|
return self.combineByKey(
|
|
|
|
lambda v: seqFunc(createZero(), v), seqFunc, combFunc, numPartitions)
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2014-03-10 16:37:11 -04:00
|
|
|
def foldByKey(self, zeroValue, func, numPartitions=None):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Merge the values for each key using an associative function "func"
|
|
|
|
and a neutral "zeroValue" which may be added to the result an
|
|
|
|
arbitrary number of times, and must not change the result
|
|
|
|
(e.g., 0 for addition, or 1 for multiplication.).
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-03-10 16:37:11 -04:00
|
|
|
>>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)])
|
|
|
|
>>> from operator import add
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> sorted(rdd.foldByKey(0, add).collect())
|
2014-03-10 16:37:11 -04:00
|
|
|
[('a', 2), ('b', 1)]
|
|
|
|
"""
|
2014-06-12 11:14:25 -04:00
|
|
|
def createZero():
|
2014-07-14 03:42:59 -04:00
|
|
|
return copy.deepcopy(zeroValue)
|
2014-06-12 11:14:25 -04:00
|
|
|
|
|
|
|
return self.combineByKey(lambda v: func(createZero(), v), func, func, numPartitions)
|
2014-06-09 03:08:40 -04:00
|
|
|
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
def _can_spill(self):
|
|
|
|
return self.ctx._conf.get("spark.shuffle.spill", "True").lower() == "true"
|
|
|
|
|
|
|
|
def _memory_limit(self):
|
|
|
|
return _parse_memory(self.ctx._conf.get("spark.python.worker.memory", "512m"))
|
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
# TODO: support variant with custom partitioner
|
2013-02-24 16:25:09 -05:00
|
|
|
def groupByKey(self, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
Group the values for each key in the RDD into a single sequence.
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
Hash-partitions the resulting RDD with numPartitions partitions.
|
2012-12-27 20:55:33 -05:00
|
|
|
|
2014-05-15 01:24:04 -04:00
|
|
|
Note: If you are grouping in order to perform an aggregation (such as a
|
2015-01-28 15:41:23 -05:00
|
|
|
sum or average) over each key, using reduceByKey or aggregateByKey will
|
|
|
|
provide much better performance.
|
2014-05-15 01:24:04 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> rdd = sc.parallelize([("a", 1), ("b", 1), ("a", 1)])
|
|
|
|
>>> sorted(rdd.groupByKey().mapValues(len).collect())
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
[('a', 2), ('b', 1)]
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> sorted(rdd.groupByKey().mapValues(list).collect())
|
2012-08-10 04:10:02 -04:00
|
|
|
[('a', [1, 1]), ('b', [1])]
|
|
|
|
"""
|
|
|
|
def createCombiner(x):
|
|
|
|
return [x]
|
|
|
|
|
|
|
|
def mergeValue(xs, x):
|
|
|
|
xs.append(x)
|
|
|
|
return xs
|
|
|
|
|
|
|
|
def mergeCombiners(a, b):
|
2014-07-25 01:53:47 -04:00
|
|
|
a.extend(b)
|
|
|
|
return a
|
2012-08-10 04:10:02 -04:00
|
|
|
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
spill = self._can_spill()
|
|
|
|
memory = self._memory_limit()
|
|
|
|
serializer = self._jrdd_deserializer
|
|
|
|
agg = Aggregator(createCombiner, mergeValue, mergeCombiners)
|
|
|
|
|
|
|
|
def combine(iterator):
|
|
|
|
merger = ExternalMerger(agg, memory * 0.9, serializer) \
|
|
|
|
if spill else InMemoryMerger(agg)
|
|
|
|
merger.mergeValues(iterator)
|
2015-04-16 19:20:57 -04:00
|
|
|
return merger.items()
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
|
|
|
|
locally_combined = self.mapPartitions(combine, preservesPartitioning=True)
|
|
|
|
shuffled = locally_combined.partitionBy(numPartitions)
|
|
|
|
|
|
|
|
def groupByKey(it):
|
|
|
|
merger = ExternalGroupBy(agg, memory, serializer)\
|
|
|
|
if spill else InMemoryMerger(agg)
|
|
|
|
merger.mergeCombiners(it)
|
2015-04-16 19:20:57 -04:00
|
|
|
return merger.items()
|
[SPARK-3074] [PySpark] support groupByKey() with single huge key
This patch change groupByKey() to use external sort based approach, so it can support single huge key.
For example, it can group by a dataset including one hot key with 40 millions values (strings), using 500M memory for Python worker, finished in about 2 minutes. (it will need 6G memory in hash based approach).
During groupByKey(), it will do in-memory groupBy first. If the dataset can not fit in memory, then data will be partitioned by hash. If one partition still can not fit in memory, it will switch to sort based groupBy().
Author: Davies Liu <davies.liu@gmail.com>
Author: Davies Liu <davies@databricks.com>
Closes #1977 from davies/groupby and squashes the following commits:
af3713a [Davies Liu] make sure it's iterator
67772dd [Davies Liu] fix tests
e78c15c [Davies Liu] address comments
0b0fde8 [Davies Liu] address comments
0dcf320 [Davies Liu] address comments, rollback changes in ResultIterable
e3b8eab [Davies Liu] fix narrow dependency
2a1857a [Davies Liu] typo
d2f053b [Davies Liu] add repr for FlattedValuesSerializer
c6a2f8d [Davies Liu] address comments
9e2df24 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
2b9c261 [Davies Liu] fix typo in comments
70aadcd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
a14b4bd [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
ab5515b [Davies Liu] Merge branch 'master' into groupby
651f891 [Davies Liu] simplify GroupByKey
1578f2e [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
1f69f93 [Davies Liu] fix tests
0d3395f [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
341f1e0 [Davies Liu] add comments, refactor
47918b8 [Davies Liu] remove unused code
6540948 [Davies Liu] address comments:
17f4ec6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into groupby
4d4bc86 [Davies Liu] bugfix
8ef965e [Davies Liu] Merge branch 'master' into groupby
fbc504a [Davies Liu] Merge branch 'master' into groupby
779ed03 [Davies Liu] fix merge conflict
2c1d05b [Davies Liu] refactor, minor turning
b48cda5 [Davies Liu] Merge branch 'master' into groupby
85138e6 [Davies Liu] Merge branch 'master' into groupby
acd8e1b [Davies Liu] fix memory when groupByKey().count()
905b233 [Davies Liu] Merge branch 'sort' into groupby
1f075ed [Davies Liu] Merge branch 'master' into sort
4b07d39 [Davies Liu] compress the data while spilling
0a081c6 [Davies Liu] Merge branch 'master' into groupby
f157fe7 [Davies Liu] Merge branch 'sort' into groupby
eb53ca6 [Davies Liu] Merge branch 'master' into sort
b2dc3bf [Davies Liu] Merge branch 'sort' into groupby
644abaf [Davies Liu] add license in LICENSE
19f7873 [Davies Liu] improve tests
11ba318 [Davies Liu] typo
085aef8 [Davies Liu] Merge branch 'master' into groupby
3ee58e5 [Davies Liu] switch to sort based groupBy, based on size of data
1ea0669 [Davies Liu] choose sort based groupByKey() automatically
b40bae7 [Davies Liu] bugfix
efa23df [Davies Liu] refactor, add spark.shuffle.sort=False
250be4e [Davies Liu] flatten the combined values when dumping into disks
d05060d [Davies Liu] group the same key before shuffle, reduce the comparison during sorting
083d842 [Davies Liu] sorted based groupByKey()
55602ee [Davies Liu] use external sort in sortBy() and sortByKey()
2015-04-09 20:07:23 -04:00
|
|
|
|
|
|
|
return shuffled.mapPartitions(groupByKey, True).mapValues(ResultIterable)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
def flatMapValues(self, f):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
|
|
|
Pass each value in the key-value pair RDD through a flatMap function
|
|
|
|
without changing the keys; this also retains the original RDD's
|
|
|
|
partitioning.
|
2014-02-22 18:10:31 -05:00
|
|
|
|
|
|
|
>>> x = sc.parallelize([("a", ["x", "y", "z"]), ("b", ["p", "r"])])
|
|
|
|
>>> def f(x): return x
|
|
|
|
>>> x.flatMapValues(f).collect()
|
|
|
|
[('a', 'x'), ('a', 'y'), ('a', 'z'), ('b', 'p'), ('b', 'r')]
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
flat_map_fn = lambda kv: ((kv[0], x) for x in f(kv[1]))
|
2012-12-27 20:55:33 -05:00
|
|
|
return self.flatMap(flat_map_fn, preservesPartitioning=True)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
def mapValues(self, f):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
|
|
|
Pass each value in the key-value pair RDD through a map function
|
|
|
|
without changing the keys; this also retains the original RDD's
|
|
|
|
partitioning.
|
2014-02-22 18:10:31 -05:00
|
|
|
|
|
|
|
>>> x = sc.parallelize([("a", ["apple", "banana", "lemon"]), ("b", ["grapes"])])
|
|
|
|
>>> def f(x): return len(x)
|
|
|
|
>>> x.mapValues(f).collect()
|
|
|
|
[('a', 3), ('b', 1)]
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
map_values_fn = lambda kv: (kv[0], f(kv[1]))
|
2012-08-18 19:07:10 -04:00
|
|
|
return self.map(map_values_fn, preservesPartitioning=True)
|
|
|
|
|
2014-06-20 14:03:03 -04:00
|
|
|
def groupWith(self, other, *others):
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2014-06-20 14:03:03 -04:00
|
|
|
Alias for cogroup but with support for multiple RDDs.
|
|
|
|
|
|
|
|
>>> w = sc.parallelize([("a", 5), ("b", 6)])
|
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4)])
|
|
|
|
>>> y = sc.parallelize([("a", 2)])
|
|
|
|
>>> z = sc.parallelize([("b", 42)])
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> [(x, tuple(map(list, y))) for x, y in sorted(list(w.groupWith(x, y, z).collect()))]
|
2014-06-20 14:03:03 -04:00
|
|
|
[('a', ([5], [1], [2], [])), ('b', ([6], [4], [], [42]))]
|
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
"""
|
2014-06-20 14:03:03 -04:00
|
|
|
return python_cogroup((self, other) + others, numPartitions=None)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2012-12-27 20:55:33 -05:00
|
|
|
# TODO: add variant with custom parittioner
|
2013-02-24 16:25:09 -05:00
|
|
|
def cogroup(self, other, numPartitions=None):
|
2012-08-10 04:10:02 -04:00
|
|
|
"""
|
2012-12-27 20:55:33 -05:00
|
|
|
For each key k in C{self} or C{other}, return a resulting RDD that
|
2014-06-12 22:44:27 -04:00
|
|
|
contains a tuple with the list of values for that key in C{self} as
|
|
|
|
well as C{other}.
|
2012-12-27 20:55:33 -05:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4)])
|
|
|
|
>>> y = sc.parallelize([("a", 2)])
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> [(x, tuple(map(list, y))) for x, y in sorted(list(x.cogroup(y).collect()))]
|
2012-08-10 04:10:02 -04:00
|
|
|
[('a', ([1], [2])), ('b', ([4], []))]
|
|
|
|
"""
|
2014-06-20 14:03:03 -04:00
|
|
|
return python_cogroup((self, other), numPartitions)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-07-25 02:42:08 -04:00
|
|
|
def sampleByKey(self, withReplacement, fractions, seed=None):
|
|
|
|
"""
|
|
|
|
Return a subset of this RDD sampled by key (via stratified sampling).
|
|
|
|
Create a sample of this RDD using variable sampling rates for
|
|
|
|
different keys as specified by fractions, a key to sampling rate map.
|
|
|
|
|
|
|
|
>>> fractions = {"a": 0.2, "b": 0.1}
|
|
|
|
>>> rdd = sc.parallelize(fractions.keys()).cartesian(sc.parallelize(range(0, 1000)))
|
|
|
|
>>> sample = dict(rdd.sampleByKey(False, fractions, 2).groupByKey().collect())
|
|
|
|
>>> 100 < len(sample["a"]) < 300 and 50 < len(sample["b"]) < 150
|
|
|
|
True
|
|
|
|
>>> max(sample["a"]) <= 999 and min(sample["a"]) >= 0
|
|
|
|
True
|
|
|
|
>>> max(sample["b"]) <= 999 and min(sample["b"]) >= 0
|
|
|
|
True
|
|
|
|
"""
|
|
|
|
for fraction in fractions.values():
|
|
|
|
assert fraction >= 0.0, "Negative fraction value: %s" % fraction
|
2014-08-06 15:58:24 -04:00
|
|
|
return self.mapPartitionsWithIndex(
|
2014-07-25 02:42:08 -04:00
|
|
|
RDDStratifiedSampler(withReplacement, fractions, seed).func, True)
|
|
|
|
|
2013-08-28 19:10:38 -04:00
|
|
|
def subtractByKey(self, other, numPartitions=None):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Return each (key, value) pair in C{self} that has no pair with matching
|
|
|
|
key in C{other}.
|
2013-08-28 19:10:38 -04:00
|
|
|
|
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4), ("b", 5), ("a", 2)])
|
|
|
|
>>> y = sc.parallelize([("a", 3), ("c", None)])
|
|
|
|
>>> sorted(x.subtractByKey(y).collect())
|
|
|
|
[('b', 4), ('b', 5)]
|
2013-10-09 15:08:04 -04:00
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
def filter_func(pair):
|
|
|
|
key, (val1, val2) = pair
|
|
|
|
return val1 and not val2
|
2014-08-27 16:18:33 -04:00
|
|
|
return self.cogroup(other, numPartitions).filter(filter_func).flatMapValues(lambda x: x[0])
|
2013-08-28 19:10:38 -04:00
|
|
|
|
|
|
|
def subtract(self, other, numPartitions=None):
|
|
|
|
"""
|
|
|
|
Return each value in C{self} that is not contained in C{other}.
|
|
|
|
|
|
|
|
>>> x = sc.parallelize([("a", 1), ("b", 4), ("b", 5), ("a", 3)])
|
|
|
|
>>> y = sc.parallelize([("a", 3), ("c", None)])
|
|
|
|
>>> sorted(x.subtract(y).collect())
|
|
|
|
[('a', 1), ('b', 4), ('b', 5)]
|
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
# note: here 'True' is just a placeholder
|
|
|
|
rdd = other.map(lambda x: (x, True))
|
2014-08-27 16:18:33 -04:00
|
|
|
return self.map(lambda x: (x, True)).subtractByKey(rdd, numPartitions).keys()
|
2013-08-28 19:10:38 -04:00
|
|
|
|
|
|
|
def keyBy(self, f):
|
|
|
|
"""
|
|
|
|
Creates tuples of the elements in this RDD by applying C{f}.
|
|
|
|
|
|
|
|
>>> x = sc.parallelize(range(0,3)).keyBy(lambda x: x*x)
|
|
|
|
>>> y = sc.parallelize(zip(range(0,5), range(0,5)))
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> [(x, list(map(list, y))) for x, y in sorted(x.cogroup(y).collect())]
|
|
|
|
[(0, [[0], [0]]), (1, [[1], [1]]), (2, [[], [2]]), (3, [[], [3]]), (4, [[2], [4]])]
|
2013-08-28 19:10:38 -04:00
|
|
|
"""
|
|
|
|
return self.map(lambda x: (f(x), x))
|
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
def repartition(self, numPartitions):
|
|
|
|
"""
|
|
|
|
Return a new RDD that has exactly numPartitions partitions.
|
2014-06-09 03:08:40 -04:00
|
|
|
|
2014-06-12 22:44:27 -04:00
|
|
|
Can increase or decrease the level of parallelism in this RDD.
|
|
|
|
Internally, this uses a shuffle to redistribute data.
|
|
|
|
If you are decreasing the number of partitions in this RDD, consider
|
|
|
|
using `coalesce`, which can avoid performing a shuffle.
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
>>> rdd = sc.parallelize([1,2,3,4,5,6,7], 4)
|
|
|
|
>>> sorted(rdd.glom().collect())
|
|
|
|
[[1], [2, 3], [4, 5], [6, 7]]
|
|
|
|
>>> len(rdd.repartition(2).glom().collect())
|
|
|
|
2
|
|
|
|
>>> len(rdd.repartition(10).glom().collect())
|
|
|
|
10
|
|
|
|
"""
|
|
|
|
jrdd = self._jrdd.repartition(numPartitions)
|
|
|
|
return RDD(jrdd, self.ctx, self._jrdd_deserializer)
|
|
|
|
|
|
|
|
def coalesce(self, numPartitions, shuffle=False):
|
|
|
|
"""
|
|
|
|
Return a new RDD that is reduced into `numPartitions` partitions.
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2014-02-06 17:58:35 -05:00
|
|
|
>>> sc.parallelize([1, 2, 3, 4, 5], 3).glom().collect()
|
|
|
|
[[1], [2, 3], [4, 5]]
|
|
|
|
>>> sc.parallelize([1, 2, 3, 4, 5], 3).coalesce(1).glom().collect()
|
|
|
|
[[1, 2, 3, 4, 5]]
|
|
|
|
"""
|
|
|
|
jrdd = self._jrdd.coalesce(numPartitions)
|
|
|
|
return RDD(jrdd, self.ctx, self._jrdd_deserializer)
|
|
|
|
|
2014-03-10 16:27:00 -04:00
|
|
|
def zip(self, other):
|
|
|
|
"""
|
2014-06-12 22:44:27 -04:00
|
|
|
Zips this RDD with another one, returning key-value pairs with the
|
|
|
|
first element in each RDD second element in each RDD, etc. Assumes
|
|
|
|
that the two RDDs have the same number of partitions and the same
|
|
|
|
number of elements in each partition (e.g. one was made through
|
2014-03-10 16:27:00 -04:00
|
|
|
a map on the other).
|
|
|
|
|
|
|
|
>>> x = sc.parallelize(range(0,5))
|
|
|
|
>>> y = sc.parallelize(range(1000, 1005))
|
|
|
|
>>> x.zip(y).collect()
|
|
|
|
[(0, 1000), (1, 1001), (2, 1002), (3, 1003), (4, 1004)]
|
|
|
|
"""
|
2014-08-19 17:46:32 -04:00
|
|
|
def get_batch_size(ser):
|
|
|
|
if isinstance(ser, BatchedSerializer):
|
|
|
|
return ser.batchSize
|
2014-12-16 01:58:26 -05:00
|
|
|
return 1 # not batched
|
2014-08-19 17:46:32 -04:00
|
|
|
|
|
|
|
def batch_as(rdd, batchSize):
|
2014-12-16 01:58:26 -05:00
|
|
|
return rdd._reserialize(BatchedSerializer(PickleSerializer(), batchSize))
|
2014-08-19 17:46:32 -04:00
|
|
|
|
|
|
|
my_batch = get_batch_size(self._jrdd_deserializer)
|
|
|
|
other_batch = get_batch_size(other._jrdd_deserializer)
|
2015-02-24 17:50:00 -05:00
|
|
|
if my_batch != other_batch or not my_batch:
|
2014-12-16 01:58:26 -05:00
|
|
|
# use the smallest batchSize for both of them
|
|
|
|
batchSize = min(my_batch, other_batch)
|
|
|
|
if batchSize <= 0:
|
|
|
|
# auto batched or unlimited
|
|
|
|
batchSize = 100
|
|
|
|
other = batch_as(other, batchSize)
|
|
|
|
self = batch_as(self, batchSize)
|
2014-11-04 02:56:14 -05:00
|
|
|
|
|
|
|
if self.getNumPartitions() != other.getNumPartitions():
|
|
|
|
raise ValueError("Can only zip with RDD which has the same number of partitions")
|
2014-08-19 17:46:32 -04:00
|
|
|
|
|
|
|
# There will be an Exception in JVM if there are different number
|
|
|
|
# of items in each partitions.
|
2014-03-10 16:27:00 -04:00
|
|
|
pairRDD = self._jrdd.zip(other._jrdd)
|
|
|
|
deserializer = PairDeserializer(self._jrdd_deserializer,
|
2014-07-14 03:42:59 -04:00
|
|
|
other._jrdd_deserializer)
|
2014-03-10 16:27:00 -04:00
|
|
|
return RDD(pairRDD, self.ctx, deserializer)
|
|
|
|
|
[SPARK-2871] [PySpark] add zipWithIndex() and zipWithUniqueId()
RDD.zipWithIndex()
Zips this RDD with its element indices.
The ordering is first based on the partition index and then the
ordering of items within each partition. So the first item in
the first partition gets index 0, and the last item in the last
partition receives the largest index.
This method needs to trigger a spark job when this RDD contains
more than one partitions.
>>> sc.parallelize(range(4), 2).zipWithIndex().collect()
[(0, 0), (1, 1), (2, 2), (3, 3)]
RDD.zipWithUniqueId()
Zips this RDD with generated unique Long ids.
Items in the kth partition will get ids k, n+k, 2*n+k, ..., where
n is the number of partitions. So there may exist gaps, but this
method won't trigger a spark job, which is different from
L{zipWithIndex}
>>> sc.parallelize(range(4), 2).zipWithUniqueId().collect()
[(0, 0), (2, 1), (1, 2), (3, 3)]
Author: Davies Liu <davies.liu@gmail.com>
Closes #2092 from davies/zipWith and squashes the following commits:
cebe5bf [Davies Liu] improve test cases, reverse the order of index
0d2a128 [Davies Liu] add zipWithIndex() and zipWithUniqueId()
2014-08-25 00:16:05 -04:00
|
|
|
def zipWithIndex(self):
|
|
|
|
"""
|
|
|
|
Zips this RDD with its element indices.
|
|
|
|
|
|
|
|
The ordering is first based on the partition index and then the
|
|
|
|
ordering of items within each partition. So the first item in
|
|
|
|
the first partition gets index 0, and the last item in the last
|
|
|
|
partition receives the largest index.
|
|
|
|
|
|
|
|
This method needs to trigger a spark job when this RDD contains
|
|
|
|
more than one partitions.
|
|
|
|
|
|
|
|
>>> sc.parallelize(["a", "b", "c", "d"], 3).zipWithIndex().collect()
|
|
|
|
[('a', 0), ('b', 1), ('c', 2), ('d', 3)]
|
|
|
|
"""
|
|
|
|
starts = [0]
|
|
|
|
if self.getNumPartitions() > 1:
|
|
|
|
nums = self.mapPartitions(lambda it: [sum(1 for i in it)]).collect()
|
|
|
|
for i in range(len(nums) - 1):
|
|
|
|
starts.append(starts[-1] + nums[i])
|
|
|
|
|
|
|
|
def func(k, it):
|
|
|
|
for i, v in enumerate(it, starts[k]):
|
|
|
|
yield v, i
|
|
|
|
|
|
|
|
return self.mapPartitionsWithIndex(func)
|
|
|
|
|
|
|
|
def zipWithUniqueId(self):
|
|
|
|
"""
|
|
|
|
Zips this RDD with generated unique Long ids.
|
|
|
|
|
|
|
|
Items in the kth partition will get ids k, n+k, 2*n+k, ..., where
|
|
|
|
n is the number of partitions. So there may exist gaps, but this
|
|
|
|
method won't trigger a spark job, which is different from
|
|
|
|
L{zipWithIndex}
|
|
|
|
|
|
|
|
>>> sc.parallelize(["a", "b", "c", "d", "e"], 3).zipWithUniqueId().collect()
|
|
|
|
[('a', 0), ('b', 1), ('c', 4), ('d', 2), ('e', 5)]
|
|
|
|
"""
|
|
|
|
n = self.getNumPartitions()
|
|
|
|
|
|
|
|
def func(k, it):
|
|
|
|
for i, v in enumerate(it):
|
|
|
|
yield v, i * n + k
|
|
|
|
|
|
|
|
return self.mapPartitionsWithIndex(func)
|
|
|
|
|
2014-03-12 02:57:05 -04:00
|
|
|
def name(self):
|
|
|
|
"""
|
|
|
|
Return the name of this RDD.
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
n = self._jrdd.name()
|
|
|
|
if n:
|
|
|
|
return n
|
2014-03-12 02:57:05 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
@ignore_unicode_prefix
|
2014-03-12 02:57:05 -04:00
|
|
|
def setName(self, name):
|
|
|
|
"""
|
|
|
|
Assign a name to this RDD.
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> rdd1 = sc.parallelize([1, 2])
|
2014-10-31 15:07:48 -04:00
|
|
|
>>> rdd1.setName('RDD1').name()
|
2015-04-16 19:20:57 -04:00
|
|
|
u'RDD1'
|
2014-03-12 02:57:05 -04:00
|
|
|
"""
|
|
|
|
self._jrdd.setName(name)
|
2014-10-31 15:07:48 -04:00
|
|
|
return self
|
2014-03-12 02:57:05 -04:00
|
|
|
|
|
|
|
def toDebugString(self):
|
|
|
|
"""
|
|
|
|
A description of this RDD and its recursive dependencies for debugging.
|
|
|
|
"""
|
|
|
|
debug_string = self._jrdd.toDebugString()
|
2014-08-27 16:18:33 -04:00
|
|
|
if debug_string:
|
|
|
|
return debug_string.encode('utf-8')
|
2014-03-12 02:57:05 -04:00
|
|
|
|
|
|
|
def getStorageLevel(self):
|
|
|
|
"""
|
|
|
|
Get the RDD's current storage level.
|
2014-06-17 02:31:31 -04:00
|
|
|
|
2014-03-12 02:57:05 -04:00
|
|
|
>>> rdd1 = sc.parallelize([1,2])
|
|
|
|
>>> rdd1.getStorageLevel()
|
2014-04-04 23:36:24 -04:00
|
|
|
StorageLevel(False, False, False, False, 1)
|
2014-06-17 02:31:31 -04:00
|
|
|
>>> print(rdd1.getStorageLevel())
|
|
|
|
Serialized 1x Replicated
|
2014-03-12 02:57:05 -04:00
|
|
|
"""
|
|
|
|
java_storage_level = self._jrdd.getStorageLevel()
|
|
|
|
storage_level = StorageLevel(java_storage_level.useDisk(),
|
|
|
|
java_storage_level.useMemory(),
|
2014-04-04 23:36:24 -04:00
|
|
|
java_storage_level.useOffHeap(),
|
2014-03-12 02:57:05 -04:00
|
|
|
java_storage_level.deserialized(),
|
|
|
|
java_storage_level.replication())
|
|
|
|
return storage_level
|
2014-03-10 16:27:00 -04:00
|
|
|
|
2014-06-20 03:06:57 -04:00
|
|
|
def _defaultReducePartitions(self):
|
|
|
|
"""
|
|
|
|
Returns the default number of partitions to use during reduce tasks (e.g., groupBy).
|
|
|
|
If spark.default.parallelism is set, then we'll use the value from SparkContext
|
|
|
|
defaultParallelism, otherwise we'll use the number of partitions in this RDD.
|
|
|
|
|
|
|
|
This mirrors the behavior of the Scala Partitioner#defaultPartitioner, intended to reduce
|
|
|
|
the likelihood of OOMs. Once PySpark adopts Partitioner-based APIs, this behavior will
|
|
|
|
be inherent.
|
|
|
|
"""
|
|
|
|
if self.ctx._conf.contains("spark.default.parallelism"):
|
|
|
|
return self.ctx.defaultParallelism
|
|
|
|
else:
|
|
|
|
return self.getNumPartitions()
|
|
|
|
|
2014-08-27 16:18:33 -04:00
|
|
|
def lookup(self, key):
|
|
|
|
"""
|
|
|
|
Return the list of values in the RDD for key `key`. This operation
|
|
|
|
is done efficiently if the RDD has a known partitioner by only
|
|
|
|
searching the partition that the key maps to.
|
|
|
|
|
|
|
|
>>> l = range(1000)
|
|
|
|
>>> rdd = sc.parallelize(zip(l, l), 10)
|
|
|
|
>>> rdd.lookup(42) # slow
|
|
|
|
[42]
|
|
|
|
>>> sorted = rdd.sortByKey()
|
|
|
|
>>> sorted.lookup(42) # fast
|
|
|
|
[42]
|
|
|
|
>>> sorted.lookup(1024)
|
|
|
|
[]
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
values = self.filter(lambda kv: kv[0] == key).values()
|
2014-08-27 16:18:33 -04:00
|
|
|
|
2015-02-17 19:54:57 -05:00
|
|
|
if self.partitioner is not None:
|
|
|
|
return self.ctx.runJob(values, lambda x: x, [self.partitioner(key)], False)
|
2014-08-27 16:18:33 -04:00
|
|
|
|
|
|
|
return values.collect()
|
2012-08-10 04:10:02 -04:00
|
|
|
|
2014-09-02 18:47:47 -04:00
|
|
|
def _to_java_object_rdd(self):
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
""" Return an JavaRDD of Object by unpickling
|
|
|
|
|
|
|
|
It will convert each Python object into Java object by Pyrolite, whenever the
|
|
|
|
RDD is serialized in batch or not.
|
|
|
|
"""
|
2014-11-04 02:56:14 -05:00
|
|
|
rdd = self._pickled()
|
|
|
|
return self.ctx._jvm.SerDeUtil.pythonToJava(rdd._jrdd, True)
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
|
|
|
|
def countApprox(self, timeout, confidence=0.95):
|
|
|
|
"""
|
2014-12-17 20:31:24 -05:00
|
|
|
.. note:: Experimental
|
2015-02-25 18:13:34 -05:00
|
|
|
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
Approximate version of count() that returns a potentially incomplete
|
|
|
|
result within a timeout, even if not all tasks have finished.
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize(range(1000), 10)
|
|
|
|
>>> rdd.countApprox(1000, 1.0)
|
|
|
|
1000
|
|
|
|
"""
|
|
|
|
drdd = self.mapPartitions(lambda it: [float(sum(1 for i in it))])
|
|
|
|
return int(drdd.sumApprox(timeout, confidence))
|
|
|
|
|
|
|
|
def sumApprox(self, timeout, confidence=0.95):
|
|
|
|
"""
|
2014-12-17 20:31:24 -05:00
|
|
|
.. note:: Experimental
|
2015-02-25 18:13:34 -05:00
|
|
|
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
Approximate operation to return the sum within a timeout
|
|
|
|
or meet the confidence.
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize(range(1000), 10)
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> r = sum(range(1000))
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
>>> (rdd.sumApprox(1000) - r) / r < 0.05
|
|
|
|
True
|
|
|
|
"""
|
2014-09-02 18:47:47 -04:00
|
|
|
jrdd = self.mapPartitions(lambda it: [float(sum(it))])._to_java_object_rdd()
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
jdrdd = self.ctx._jvm.JavaDoubleRDD.fromRDD(jrdd.rdd())
|
|
|
|
r = jdrdd.sumApprox(timeout, confidence).getFinalValue()
|
|
|
|
return BoundedFloat(r.mean(), r.confidence(), r.low(), r.high())
|
|
|
|
|
|
|
|
def meanApprox(self, timeout, confidence=0.95):
|
|
|
|
"""
|
2014-12-17 20:31:24 -05:00
|
|
|
.. note:: Experimental
|
2015-02-25 18:13:34 -05:00
|
|
|
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
Approximate operation to return the mean within a timeout
|
|
|
|
or meet the confidence.
|
|
|
|
|
|
|
|
>>> rdd = sc.parallelize(range(1000), 10)
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> r = sum(range(1000)) / 1000.0
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
>>> (rdd.meanApprox(1000) - r) / r < 0.05
|
|
|
|
True
|
|
|
|
"""
|
2014-09-02 18:47:47 -04:00
|
|
|
jrdd = self.map(float)._to_java_object_rdd()
|
[SPARK-2871] [PySpark] add approx API for RDD
RDD.countApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate version of count() that returns a potentially incomplete
result within a timeout, even if not all tasks have finished.
>>> rdd = sc.parallelize(range(1000), 10)
>>> rdd.countApprox(1000, 1.0)
1000
RDD.sumApprox(self, timeout, confidence=0.95)
Approximate operation to return the sum within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000))
>>> (rdd.sumApprox(1000) - r) / r < 0.05
RDD.meanApprox(self, timeout, confidence=0.95)
:: Experimental ::
Approximate operation to return the mean within a timeout
or meet the confidence.
>>> rdd = sc.parallelize(range(1000), 10)
>>> r = sum(xrange(1000)) / 1000.0
>>> (rdd.meanApprox(1000) - r) / r < 0.05
True
Author: Davies Liu <davies.liu@gmail.com>
Closes #2095 from davies/approx and squashes the following commits:
e8c252b [Davies Liu] add approx API for RDD
2014-08-23 22:33:34 -04:00
|
|
|
jdrdd = self.ctx._jvm.JavaDoubleRDD.fromRDD(jrdd.rdd())
|
|
|
|
r = jdrdd.meanApprox(timeout, confidence).getFinalValue()
|
|
|
|
return BoundedFloat(r.mean(), r.confidence(), r.low(), r.high())
|
|
|
|
|
2014-09-02 18:47:47 -04:00
|
|
|
def countApproxDistinct(self, relativeSD=0.05):
|
|
|
|
"""
|
2014-12-17 20:31:24 -05:00
|
|
|
.. note:: Experimental
|
2015-02-25 18:13:34 -05:00
|
|
|
|
2014-09-02 18:47:47 -04:00
|
|
|
Return approximate number of distinct elements in the RDD.
|
|
|
|
|
|
|
|
The algorithm used is based on streamlib's implementation of
|
|
|
|
"HyperLogLog in Practice: Algorithmic Engineering of a State
|
|
|
|
of The Art Cardinality Estimation Algorithm", available
|
|
|
|
<a href="http://dx.doi.org/10.1145/2452376.2452456">here</a>.
|
|
|
|
|
2014-10-11 14:51:59 -04:00
|
|
|
:param relativeSD: Relative accuracy. Smaller values create
|
2014-09-02 18:47:47 -04:00
|
|
|
counters that require more space.
|
|
|
|
It must be greater than 0.000017.
|
|
|
|
|
|
|
|
>>> n = sc.parallelize(range(1000)).map(str).countApproxDistinct()
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> 900 < n < 1100
|
2014-09-02 18:47:47 -04:00
|
|
|
True
|
|
|
|
>>> n = sc.parallelize([i % 20 for i in range(1000)]).countApproxDistinct()
|
2015-04-16 19:20:57 -04:00
|
|
|
>>> 16 < n < 24
|
2014-09-02 18:47:47 -04:00
|
|
|
True
|
|
|
|
"""
|
|
|
|
if relativeSD < 0.000017:
|
|
|
|
raise ValueError("relativeSD should be greater than 0.000017")
|
|
|
|
# the hash space in Java is 2^32
|
|
|
|
hashRDD = self.map(lambda x: portable_hash(x) & 0xFFFFFFFF)
|
|
|
|
return hashRDD._to_java_object_rdd().countApproxDistinct(relativeSD)
|
|
|
|
|
2015-01-28 15:47:12 -05:00
|
|
|
def toLocalIterator(self):
|
|
|
|
"""
|
|
|
|
Return an iterator that contains all of the elements in this RDD.
|
|
|
|
The iterator will consume as much memory as the largest partition in this RDD.
|
|
|
|
>>> rdd = sc.parallelize(range(10))
|
|
|
|
>>> [x for x in rdd.toLocalIterator()]
|
|
|
|
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
|
|
|
|
"""
|
2015-04-16 19:20:57 -04:00
|
|
|
for partition in range(self.getNumPartitions()):
|
2015-01-28 15:47:12 -05:00
|
|
|
rows = self.context.runJob(self, lambda x: x, [partition])
|
|
|
|
for row in rows:
|
|
|
|
yield row
|
|
|
|
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2015-02-04 18:55:09 -05:00
|
|
|
def _prepare_for_python_RDD(sc, command, obj=None):
|
|
|
|
# the serialized command will be compressed by broadcast
|
|
|
|
ser = CloudPickleSerializer()
|
2015-04-10 17:04:53 -04:00
|
|
|
pickled_command = ser.dumps((command, sys.version_info[:2]))
|
2015-02-04 18:55:09 -05:00
|
|
|
if len(pickled_command) > (1 << 20): # 1M
|
2015-04-15 15:58:02 -04:00
|
|
|
# The broadcast will have same life cycle as created PythonRDD
|
2015-02-04 18:55:09 -05:00
|
|
|
broadcast = sc.broadcast(pickled_command)
|
|
|
|
pickled_command = ser.dumps(broadcast)
|
2015-04-21 03:08:18 -04:00
|
|
|
# There is a bug in py4j.java_gateway.JavaClass with auto_convert
|
|
|
|
# https://github.com/bartdag/py4j/issues/161
|
|
|
|
# TODO: use auto_convert once py4j fix the bug
|
2015-02-04 18:55:09 -05:00
|
|
|
broadcast_vars = ListConverter().convert(
|
|
|
|
[x._jbroadcast for x in sc._pickled_broadcast_vars],
|
|
|
|
sc._gateway._gateway_client)
|
|
|
|
sc._pickled_broadcast_vars.clear()
|
|
|
|
env = MapConverter().convert(sc.environment, sc._gateway._gateway_client)
|
|
|
|
includes = ListConverter().convert(sc._python_includes, sc._gateway._gateway_client)
|
|
|
|
return pickled_command, broadcast_vars, env, includes
|
|
|
|
|
|
|
|
|
2012-08-24 22:38:50 -04:00
|
|
|
class PipelinedRDD(RDD):
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
"""
|
|
|
|
Pipelined maps:
|
2014-08-06 17:12:21 -04:00
|
|
|
|
2012-08-18 19:07:10 -04:00
|
|
|
>>> rdd = sc.parallelize([1, 2, 3, 4])
|
|
|
|
>>> rdd.map(lambda x: 2 * x).cache().map(lambda x: 2 * x).collect()
|
|
|
|
[4, 8, 12, 16]
|
|
|
|
>>> rdd.map(lambda x: 2 * x).map(lambda x: 2 * x).collect()
|
|
|
|
[4, 8, 12, 16]
|
|
|
|
|
|
|
|
Pipelined reduces:
|
|
|
|
>>> from operator import add
|
|
|
|
>>> rdd.map(lambda x: 2 * x).reduce(add)
|
|
|
|
20
|
|
|
|
>>> rdd.flatMap(lambda x: [x, x]).reduce(add)
|
|
|
|
20
|
|
|
|
"""
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2012-08-24 22:38:50 -04:00
|
|
|
def __init__(self, prev, func, preservesPartitioning=False):
|
2013-11-05 20:52:39 -05:00
|
|
|
if not isinstance(prev, PipelinedRDD) or not prev._is_pipelinable():
|
|
|
|
# This transformation is the first in its stage:
|
|
|
|
self.func = func
|
|
|
|
self.preservesPartitioning = preservesPartitioning
|
|
|
|
self._prev_jrdd = prev._jrdd
|
|
|
|
self._prev_jrdd_deserializer = prev._jrdd_deserializer
|
|
|
|
else:
|
2012-08-10 04:10:02 -04:00
|
|
|
prev_func = prev.func
|
2014-07-14 03:42:59 -04:00
|
|
|
|
2013-01-08 19:04:41 -05:00
|
|
|
def pipeline_func(split, iterator):
|
|
|
|
return func(split, prev_func(split, iterator))
|
2012-08-24 22:38:50 -04:00
|
|
|
self.func = pipeline_func
|
2012-08-10 04:10:02 -04:00
|
|
|
self.preservesPartitioning = \
|
|
|
|
prev.preservesPartitioning and preservesPartitioning
|
2013-11-05 20:52:39 -05:00
|
|
|
self._prev_jrdd = prev._prev_jrdd # maintain the pipeline
|
|
|
|
self._prev_jrdd_deserializer = prev._prev_jrdd_deserializer
|
2012-08-10 04:10:02 -04:00
|
|
|
self.is_cached = False
|
2013-01-20 16:59:45 -05:00
|
|
|
self.is_checkpointed = False
|
2012-08-10 04:10:02 -04:00
|
|
|
self.ctx = prev.ctx
|
|
|
|
self.prev = prev
|
|
|
|
self._jrdd_val = None
|
2014-09-06 19:12:29 -04:00
|
|
|
self._id = None
|
2013-11-05 20:52:39 -05:00
|
|
|
self._jrdd_deserializer = self.ctx.serializer
|
2012-08-25 19:46:07 -04:00
|
|
|
self._bypass_serializer = False
|
2015-02-17 19:54:57 -05:00
|
|
|
self.partitioner = prev.partitioner if self.preservesPartitioning else None
|
2014-10-01 14:21:34 -04:00
|
|
|
|
2015-04-15 15:58:02 -04:00
|
|
|
def getNumPartitions(self):
|
|
|
|
return self._prev_jrdd.partitions().size()
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
@property
|
|
|
|
def _jrdd(self):
|
2012-08-25 19:46:07 -04:00
|
|
|
if self._jrdd_val:
|
|
|
|
return self._jrdd_val
|
2013-11-05 20:52:39 -05:00
|
|
|
if self._bypass_serializer:
|
2014-06-03 21:18:25 -04:00
|
|
|
self._jrdd_deserializer = NoOpSerializer()
|
2015-01-28 16:48:06 -05:00
|
|
|
|
|
|
|
if self.ctx.profiler_collector:
|
|
|
|
profiler = self.ctx.profiler_collector.new_profiler(self.ctx)
|
|
|
|
else:
|
|
|
|
profiler = None
|
|
|
|
|
|
|
|
command = (self.func, profiler, self._prev_jrdd_deserializer,
|
2014-06-03 21:18:25 -04:00
|
|
|
self._jrdd_deserializer)
|
2015-02-04 18:55:09 -05:00
|
|
|
pickled_cmd, bvars, env, includes = _prepare_for_python_RDD(self.ctx, command, self)
|
2013-02-01 14:09:56 -05:00
|
|
|
python_rdd = self.ctx._jvm.PythonRDD(self._prev_jrdd.rdd(),
|
2015-02-04 18:55:09 -05:00
|
|
|
bytearray(pickled_cmd),
|
2014-07-14 03:42:59 -04:00
|
|
|
env, includes, self.preservesPartitioning,
|
|
|
|
self.ctx.pythonExec,
|
2015-02-04 18:55:09 -05:00
|
|
|
bvars, self.ctx._javaAccumulator)
|
2012-08-25 19:46:07 -04:00
|
|
|
self._jrdd_val = python_rdd.asJavaRDD()
|
[SPARK-3478] [PySpark] Profile the Python tasks
This patch add profiling support for PySpark, it will show the profiling results
before the driver exits, here is one example:
```
============================================================
Profile of RDD<id=3>
============================================================
5146507 function calls (5146487 primitive calls) in 71.094 seconds
Ordered by: internal time, cumulative time
ncalls tottime percall cumtime percall filename:lineno(function)
5144576 68.331 0.000 68.331 0.000 statcounter.py:44(merge)
20 2.735 0.137 71.071 3.554 statcounter.py:33(__init__)
20 0.017 0.001 0.017 0.001 {cPickle.dumps}
1024 0.003 0.000 0.003 0.000 t.py:16(<lambda>)
20 0.001 0.000 0.001 0.000 {reduce}
21 0.001 0.000 0.001 0.000 {cPickle.loads}
20 0.001 0.000 0.001 0.000 copy_reg.py:95(_slotnames)
41 0.001 0.000 0.001 0.000 serializers.py:461(read_int)
40 0.001 0.000 0.002 0.000 serializers.py:179(_batched)
62 0.000 0.000 0.000 0.000 {method 'read' of 'file' objects}
20 0.000 0.000 71.072 3.554 rdd.py:863(<lambda>)
20 0.000 0.000 0.001 0.000 serializers.py:198(load_stream)
40/20 0.000 0.000 71.072 3.554 rdd.py:2093(pipeline_func)
41 0.000 0.000 0.002 0.000 serializers.py:130(load_stream)
40 0.000 0.000 71.072 1.777 rdd.py:304(func)
20 0.000 0.000 71.094 3.555 worker.py:82(process)
```
Also, use can show profile result manually by `sc.show_profiles()` or dump it into disk
by `sc.dump_profiles(path)`, such as
```python
>>> sc._conf.set("spark.python.profile", "true")
>>> rdd = sc.parallelize(range(100)).map(str)
>>> rdd.count()
100
>>> sc.show_profiles()
============================================================
Profile of RDD<id=1>
============================================================
284 function calls (276 primitive calls) in 0.001 seconds
Ordered by: internal time, cumulative time
ncalls tottime percall cumtime percall filename:lineno(function)
4 0.000 0.000 0.000 0.000 serializers.py:198(load_stream)
4 0.000 0.000 0.000 0.000 {reduce}
12/4 0.000 0.000 0.001 0.000 rdd.py:2092(pipeline_func)
4 0.000 0.000 0.000 0.000 {cPickle.loads}
4 0.000 0.000 0.000 0.000 {cPickle.dumps}
104 0.000 0.000 0.000 0.000 rdd.py:852(<genexpr>)
8 0.000 0.000 0.000 0.000 serializers.py:461(read_int)
12 0.000 0.000 0.000 0.000 rdd.py:303(func)
```
The profiling is disabled by default, can be enabled by "spark.python.profile=true".
Also, users can dump the results into disks automatically for future analysis, by "spark.python.profile.dump=path_to_dump"
This is bugfix of #2351 cc JoshRosen
Author: Davies Liu <davies.liu@gmail.com>
Closes #2556 from davies/profiler and squashes the following commits:
e68df5a [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
858e74c [Davies Liu] compatitable with python 2.6
7ef2aa0 [Davies Liu] bugfix, add tests for show_profiles and dump_profiles()
2b0daf2 [Davies Liu] fix docs
7a56c24 [Davies Liu] bugfix
cba9463 [Davies Liu] move show_profiles and dump_profiles to SparkContext
fb9565b [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
116d52a [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
09d02c3 [Davies Liu] Merge branch 'master' into profiler
c23865c [Davies Liu] Merge branch 'master' into profiler
15d6f18 [Davies Liu] add docs for two configs
dadee1a [Davies Liu] add docs string and clear profiles after show or dump
4f8309d [Davies Liu] address comment, add tests
0a5b6eb [Davies Liu] fix Python UDF
4b20494 [Davies Liu] add profile for python
2014-09-30 21:24:57 -04:00
|
|
|
|
2015-01-28 16:48:06 -05:00
|
|
|
if profiler:
|
[SPARK-3478] [PySpark] Profile the Python tasks
This patch add profiling support for PySpark, it will show the profiling results
before the driver exits, here is one example:
```
============================================================
Profile of RDD<id=3>
============================================================
5146507 function calls (5146487 primitive calls) in 71.094 seconds
Ordered by: internal time, cumulative time
ncalls tottime percall cumtime percall filename:lineno(function)
5144576 68.331 0.000 68.331 0.000 statcounter.py:44(merge)
20 2.735 0.137 71.071 3.554 statcounter.py:33(__init__)
20 0.017 0.001 0.017 0.001 {cPickle.dumps}
1024 0.003 0.000 0.003 0.000 t.py:16(<lambda>)
20 0.001 0.000 0.001 0.000 {reduce}
21 0.001 0.000 0.001 0.000 {cPickle.loads}
20 0.001 0.000 0.001 0.000 copy_reg.py:95(_slotnames)
41 0.001 0.000 0.001 0.000 serializers.py:461(read_int)
40 0.001 0.000 0.002 0.000 serializers.py:179(_batched)
62 0.000 0.000 0.000 0.000 {method 'read' of 'file' objects}
20 0.000 0.000 71.072 3.554 rdd.py:863(<lambda>)
20 0.000 0.000 0.001 0.000 serializers.py:198(load_stream)
40/20 0.000 0.000 71.072 3.554 rdd.py:2093(pipeline_func)
41 0.000 0.000 0.002 0.000 serializers.py:130(load_stream)
40 0.000 0.000 71.072 1.777 rdd.py:304(func)
20 0.000 0.000 71.094 3.555 worker.py:82(process)
```
Also, use can show profile result manually by `sc.show_profiles()` or dump it into disk
by `sc.dump_profiles(path)`, such as
```python
>>> sc._conf.set("spark.python.profile", "true")
>>> rdd = sc.parallelize(range(100)).map(str)
>>> rdd.count()
100
>>> sc.show_profiles()
============================================================
Profile of RDD<id=1>
============================================================
284 function calls (276 primitive calls) in 0.001 seconds
Ordered by: internal time, cumulative time
ncalls tottime percall cumtime percall filename:lineno(function)
4 0.000 0.000 0.000 0.000 serializers.py:198(load_stream)
4 0.000 0.000 0.000 0.000 {reduce}
12/4 0.000 0.000 0.001 0.000 rdd.py:2092(pipeline_func)
4 0.000 0.000 0.000 0.000 {cPickle.loads}
4 0.000 0.000 0.000 0.000 {cPickle.dumps}
104 0.000 0.000 0.000 0.000 rdd.py:852(<genexpr>)
8 0.000 0.000 0.000 0.000 serializers.py:461(read_int)
12 0.000 0.000 0.000 0.000 rdd.py:303(func)
```
The profiling is disabled by default, can be enabled by "spark.python.profile=true".
Also, users can dump the results into disks automatically for future analysis, by "spark.python.profile.dump=path_to_dump"
This is bugfix of #2351 cc JoshRosen
Author: Davies Liu <davies.liu@gmail.com>
Closes #2556 from davies/profiler and squashes the following commits:
e68df5a [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
858e74c [Davies Liu] compatitable with python 2.6
7ef2aa0 [Davies Liu] bugfix, add tests for show_profiles and dump_profiles()
2b0daf2 [Davies Liu] fix docs
7a56c24 [Davies Liu] bugfix
cba9463 [Davies Liu] move show_profiles and dump_profiles to SparkContext
fb9565b [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
116d52a [Davies Liu] Merge branch 'master' of github.com:apache/spark into profiler
09d02c3 [Davies Liu] Merge branch 'master' into profiler
c23865c [Davies Liu] Merge branch 'master' into profiler
15d6f18 [Davies Liu] add docs for two configs
dadee1a [Davies Liu] add docs string and clear profiles after show or dump
4f8309d [Davies Liu] address comment, add tests
0a5b6eb [Davies Liu] fix Python UDF
4b20494 [Davies Liu] add profile for python
2014-09-30 21:24:57 -04:00
|
|
|
self._id = self._jrdd_val.id()
|
2015-01-28 16:48:06 -05:00
|
|
|
self.ctx.profiler_collector.add_profiler(self._id, profiler)
|
2012-08-10 04:10:02 -04:00
|
|
|
return self._jrdd_val
|
|
|
|
|
2014-09-06 19:12:29 -04:00
|
|
|
def id(self):
|
|
|
|
if self._id is None:
|
|
|
|
self._id = self._jrdd.id()
|
|
|
|
return self._id
|
|
|
|
|
2013-01-20 16:59:45 -05:00
|
|
|
def _is_pipelinable(self):
|
|
|
|
return not (self.is_cached or self.is_checkpointed)
|
|
|
|
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
def _test():
|
|
|
|
import doctest
|
|
|
|
from pyspark.context import SparkContext
|
|
|
|
globs = globals().copy()
|
2012-12-29 17:22:56 -05:00
|
|
|
# The small batch size here ensures that we see multiple batches,
|
|
|
|
# even in these small test examples:
|
2014-11-04 02:56:14 -05:00
|
|
|
globs['sc'] = SparkContext('local[4]', 'PythonTest')
|
2014-07-14 03:42:59 -04:00
|
|
|
(failure_count, test_count) = doctest.testmod(
|
|
|
|
globs=globs, optionflags=doctest.ELLIPSIS)
|
2012-08-10 04:10:02 -04:00
|
|
|
globs['sc'].stop()
|
2013-02-03 01:44:11 -05:00
|
|
|
if failure_count:
|
|
|
|
exit(-1)
|
2012-08-10 04:10:02 -04:00
|
|
|
|
|
|
|
|
|
|
|
if __name__ == "__main__":
|
|
|
|
_test()
|