158ad0bba9
This patch adds the ability to register lambda functions written in Python, Java or Scala as UDFs for use in SQL or HiveQL. Scala: ```scala registerFunction("strLenScala", (_: String).length) sql("SELECT strLenScala('test')") ``` Python: ```python sqlCtx.registerFunction("strLenPython", lambda x: len(x), IntegerType()) sqlCtx.sql("SELECT strLenPython('test')") ``` Java: ```java sqlContext.registerFunction("stringLengthJava", new UDF1<String, Integer>() { Override public Integer call(String str) throws Exception { return str.length(); } }, DataType.IntegerType); sqlContext.sql("SELECT stringLengthJava('test')"); ``` Author: Michael Armbrust <michael@databricks.com> Closes #1063 from marmbrus/udfs and squashes the following commits: 9eda0fe [Michael Armbrust] newline 747c05e [Michael Armbrust] Add some scala UDF tests. d92727d [Michael Armbrust] Merge remote-tracking branch 'apache/master' into udfs 005d684 [Michael Armbrust] Fix naming and formatting. d14dac8 [Michael Armbrust] Fix last line of autogened java files. 8135c48 [Michael Armbrust] Move UDF unit tests to pyspark. 40b0ffd [Michael Armbrust] Merge remote-tracking branch 'apache/master' into udfs 6a36890 [Michael Armbrust] Switch logging so that SQLContext can be serializable. 7a83101 [Michael Armbrust] Drop toString 795fd15 [Michael Armbrust] Try to avoid capturing SQLContext. e54fb45 [Michael Armbrust] Docs and tests. 437cbe3 [Michael Armbrust] Update use of dataTypes, fix some python tests, address review comments. 01517d6 [Michael Armbrust] Merge remote-tracking branch 'origin/master' into udfs 8e6c932 [Michael Armbrust] WIP 3f96a52 [Michael Armbrust] Merge remote-tracking branch 'origin/master' into udfs 6237c8d [Michael Armbrust] WIP 2766f0b [Michael Armbrust] Move udfs support to SQL from hive. Add support for Java UDFs. 0f7d50c [Michael Armbrust] Draft of native Spark SQL UDFs for Scala and Python. |
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catalyst | ||
core | ||
hive | ||
hive-thriftserver | ||
README.md |
Spark SQL
This module provides support for executing relational queries expressed in either SQL or a LINQ-like Scala DSL.
Spark SQL is broken up into three subprojects:
- Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
- Execution (sql/core) - A query planner / execution engine for translating Catalyst’s logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
- Hive Support (sql/hive) - Includes an extension of SQLContext called HiveContext that allows users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allows users to run queries that include Hive UDFs, UDAFs, and UDTFs.
Other dependencies for developers
In order to create new hive test cases , you will need to set several environmental variables.
export HIVE_HOME="<path to>/hive/build/dist"
export HIVE_DEV_HOME="<path to>/hive/"
export HADOOP_HOME="<path to>/hadoop-1.0.4"
Using the console
An interactive scala console can be invoked by running sbt/sbt hive/console
. From here you can execute queries and inspect the various stages of query optimization.
catalyst$ sbt/sbt hive/console
[info] Starting scala interpreter...
import org.apache.spark.sql.catalyst.analysis._
import org.apache.spark.sql.catalyst.dsl._
import org.apache.spark.sql.catalyst.errors._
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.plans.logical._
import org.apache.spark.sql.catalyst.rules._
import org.apache.spark.sql.catalyst.types._
import org.apache.spark.sql.catalyst.util._
import org.apache.spark.sql.execution
import org.apache.spark.sql.hive._
import org.apache.spark.sql.hive.TestHive._
Welcome to Scala version 2.10.4 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_45).
Type in expressions to have them evaluated.
Type :help for more information.
scala> val query = sql("SELECT * FROM (SELECT * FROM src) a")
query: org.apache.spark.sql.ExecutedQuery =
SELECT * FROM (SELECT * FROM src) a
=== Query Plan ===
Project [key#6:0.0,value#7:0.1]
HiveTableScan [key#6,value#7], (MetastoreRelation default, src, None), None
Query results are RDDs and can be operated as such.
scala> query.collect()
res8: Array[org.apache.spark.sql.execution.Row] = Array([238,val_238], [86,val_86], [311,val_311]...
You can also build further queries on top of these RDDs using the query DSL.
scala> query.where('key === 100).toRdd.collect()
res11: Array[org.apache.spark.sql.execution.Row] = Array([100,val_100], [100,val_100])
From the console you can even write rules that transform query plans. For example, the above query has redundant project operators that aren't doing anything. This redundancy can be eliminated using the transform
function that is available on all TreeNode
objects.
scala> query.logicalPlan
res1: catalyst.plans.logical.LogicalPlan =
Project {key#0,value#1}
Project {key#0,value#1}
MetastoreRelation default, src, None
scala> query.logicalPlan transform {
| case Project(projectList, child) if projectList == child.output => child
| }
res2: catalyst.plans.logical.LogicalPlan =
Project {key#0,value#1}
MetastoreRelation default, src, None