It was in the wrong package
Author: Andrew Or <andrewor14@gmail.com>
Closes#839 from andrewor14/jdbc-suite and squashes the following commits:
f948c5a [Andrew Or] cache -> cache()
b215279 [Andrew Or] Move JdbcRDDSuite to the correct package
This PR replaces the Schedulable data structures in Pool.scala with thread-safe ones from java. Note that Scala's `with SynchronizedBuffer` trait is soon to be deprecated in 2.11 because it is ["inherently unreliable"](http://www.scala-lang.org/api/2.11.0/index.html#scala.collection.mutable.SynchronizedBuffer). We should slowly drift away from `SynchronizedBuffer` in other places too.
Note that this PR introduces an API-breaking change; `sc.getAllPools` now returns an Array rather than an ArrayBuffer. This is because we want this method to return an immutable copy rather than one may potentially confuse the user if they try to modify the copy, which takes no effect on the original data structure.
Author: Andrew Or <andrewor14@gmail.com>
Closes#762 from andrewor14/pool-npe and squashes the following commits:
383e739 [Andrew Or] JavaConverters -> JavaConversions
3f32981 [Andrew Or] Merge branch 'master' of github.com:apache/spark into pool-npe
769be19 [Andrew Or] Assorted minor changes
2189247 [Andrew Or] Merge branch 'master' of github.com:apache/spark into pool-npe
05ad9e9 [Andrew Or] Fix test - contains is not the same as containsKey
0921ea0 [Andrew Or] var -> val
07d720c [Andrew Or] Synchronize Schedulable data structures
This change adds a new partitioner which allows users
to specify # of keys per partition.
Author: Syed Hashmi <shashmi@cloudera.com>
Closes#721 from syedhashmi/master and squashes the following commits:
4ca94cc [Syed Hashmi] [SPARK-1784] Add a new partitioner
JIRA issue: [SPARK-1527](https://issues.apache.org/jira/browse/SPARK-1527)
getName() only gets the last component of the file path. When deleting test-generated directories,
we should pass the generated directory's absolute path to DiskBlockManager.
Author: Ye Xianjin <advancedxy@gmail.com>
This patch had conflicts when merged, resolved by
Committer: Patrick Wendell <pwendell@gmail.com>
Closes#436 from advancedxy/SPARK-1527 and squashes the following commits:
4678bab [Ye Xianjin] change rootDir*.getname to rootDir*.getAbsolutePath so the temporary directories are deleted when the test is finished.
The solution is to wrap a try / catch / log around the posting of each event to each listener.
Author: Andrew Or <andrewor14@gmail.com>
Closes#759 from andrewor14/listener-die and squashes the following commits:
aee5107 [Andrew Or] Merge branch 'master' of github.com:apache/spark into listener-die
370939f [Andrew Or] Remove two layers of indirection
422d278 [Andrew Or] Explicitly throw an exception instead of 1 / 0
0df0e2a [Andrew Or] Try/catch and log exceptions when posting events
This patch checks top-level closure arguments to `ClosureCleaner.clean` for `return` statements and raises an exception if it finds any. This is mainly a user-friendliness addition, since programs with return statements in closure arguments will currently fail upon RDD actions with a less-than-intuitive error message.
Author: William Benton <willb@redhat.com>
Closes#717 from willb/spark-571 and squashes the following commits:
c41eb7d [William Benton] Another test case for SPARK-571
30c42f4 [William Benton] Stylistic cleanups
559b16b [William Benton] Stylistic cleanups from review
de13b79 [William Benton] Style fixes
295b6a5 [William Benton] Forbid return statements in closure arguments.
b017c47 [William Benton] Added a test for SPARK-571
Three issues related to temp files that tests generate – these should be touched up for hygiene but are not urgent.
Modules have a log4j.properties which directs the unit-test.log output file to a directory like `[module]/target/unit-test.log`. But this ends up creating `[module]/[module]/target/unit-test.log` instead of former.
The `work/` directory is not deleted by "mvn clean", in the parent and in modules. Neither is the `checkpoint/` directory created under the various external modules.
Many tests create a temp directory, which is not usually deleted. This can be largely resolved by calling `deleteOnExit()` at creation and trying to call `Utils.deleteRecursively` consistently to clean up, sometimes in an `@After` method.
_If anyone seconds the motion, I can create a more significant change that introduces a new test trait along the lines of `LocalSparkContext`, which provides management of temp directories for subclasses to take advantage of._
Author: Sean Owen <sowen@cloudera.com>
Closes#732 from srowen/SPARK-1798 and squashes the following commits:
5af578e [Sean Owen] Try to consistently delete test temp dirs and files, and set deleteOnExit() for each
b21b356 [Sean Owen] Remove work/ and checkpoint/ dirs with mvn clean
bdd0f41 [Sean Owen] Remove duplicate module dir in log4j.properties output path for tests
This patch adds better balancing when performing a repartition of an
RDD. Previously the elements in the RDD were hash partitioned, meaning
if the RDD was skewed certain partitions would end up being very large.
This commit adds load balancing of elements across the repartitioned
RDD splits. The load balancing is not perfect: a given output partition
can have up to N more elements than the average if there are N input
partitions. However, some randomization is used to minimize the
probabiliy that this happens.
Author: Patrick Wendell <pwendell@gmail.com>
Closes#727 from pwendell/load-balance and squashes the following commits:
f9da752 [Patrick Wendell] Response to Matei's feedback
acfa46a [Patrick Wendell] SPARK-1770: Load balance elements when repartitioning.
SparkSubmit ignores `--jars` for YARN client. This is a bug.
This PR also automatically adds the application jar to `spark.jar`. Previously, when running as yarn-client, you must specify the jar additionally through `--files` (because `--jars` didn't work). Now you don't have to explicitly specify it through either.
Tested on a YARN cluster.
Author: Andrew Or <andrewor14@gmail.com>
Closes#710 from andrewor14/yarn-jars and squashes the following commits:
35d1928 [Andrew Or] Merge branch 'master' of github.com:apache/spark into yarn-jars
c27bf6c [Andrew Or] For yarn-cluster and python, do not add primaryResource to spark.jar
c92c5bf [Andrew Or] Minor cleanups
269f9f3 [Andrew Or] Fix format
013d840 [Andrew Or] Fix tests
1407474 [Andrew Or] Merge branch 'master' of github.com:apache/spark into yarn-jars
3bb75e8 [Andrew Or] Allow SparkSubmit --jars to take effect in yarn-client mode
TL;DR is there is a bit of JAR hell trouble with Netty, that can be mostly resolved and will resolve a test failure.
I hit the error described at http://apache-spark-user-list.1001560.n3.nabble.com/SparkContext-startup-time-out-td1753.html while running FlumeStreamingSuite, and have for a short while (is it just me?)
velvia notes:
"I have found a workaround. If you add akka 2.2.4 to your dependencies, then everything works, probably because akka 2.2.4 brings in newer version of Jetty."
There are at least 3 versions of Netty in play in the build:
- the new Flume 1.4.0 dependency brings in io.netty:netty:3.4.0.Final, and that is the immediate problem
- the custom version of akka 2.2.3 depends on io.netty:netty:3.6.6.
- but, Spark Core directly uses io.netty:netty-all:4.0.17.Final
The POMs try to exclude other versions of netty, but are excluding org.jboss.netty:netty, when in fact older versions of io.netty:netty (not netty-all) are also an issue.
The org.jboss.netty:netty excludes are largely unnecessary. I replaced many of them with io.netty:netty exclusions until everything agreed on io.netty:netty-all:4.0.17.Final.
But this didn't work, since Akka 2.2.3 doesn't work with Netty 4.x. Down-grading to 3.6.6.Final across the board made some Spark code not compile.
If the build *keeps* io.netty:netty:3.6.6.Final as well, everything seems to work. Part of the reason seems to be that Netty 3.x used the old `org.jboss.netty` packages. This is less than ideal, but is no worse than the current situation.
So this PR resolves the issue and improves the JAR hell, even if it leaves the existing theoretical Netty 3-vs-4 conflict:
- Remove org.jboss.netty excludes where possible, for clarity; they're not needed except with Hadoop artifacts
- Add io.netty:netty excludes where needed -- except, let akka keep its io.netty:netty
- Change a bit of test code that actually depended on Netty 3.x, to use 4.x equivalent
- Update SBT build accordingly
A better change would be to update Akka far enough such that it agrees on Netty 4.x, but I don't know if that's feasible.
Author: Sean Owen <sowen@cloudera.com>
Closes#723 from srowen/SPARK-1789 and squashes the following commits:
43661b7 [Sean Owen] Update and add Netty excludes to prevent some JAR conflicts that cause test issues
This pull request contains a rebased patch from @heathermiller (https://github.com/heathermiller/spark/pull/1) to add ClassTags on Serializer and types that depend on it (Broadcast and AccumulableCollection). Putting these in the public API signatures now will allow us to use Scala Pickling for serialization down the line without breaking binary compatibility.
One question remaining is whether we also want them on Accumulator -- Accumulator is passed as part of a bigger Task or TaskResult object via the closure serializer so it doesn't seem super useful to add the ClassTag there. Broadcast and AccumulableCollection in contrast were being serialized directly.
CC @rxin, @pwendell, @heathermiller
Author: Matei Zaharia <matei@databricks.com>
Closes#700 from mateiz/spark-1708 and squashes the following commits:
1a3d8b0 [Matei Zaharia] Use fake ClassTag in Java
3b449ed [Matei Zaharia] test fix
2209a27 [Matei Zaharia] Code style fixes
9d48830 [Matei Zaharia] Add a ClassTag on Serializer and things that depend on it
Right now, SparkSubmit ignores the `--name` flag for both yarn-client and yarn-cluster. This is a bug.
In client mode, SparkSubmit treats `--name` as a [cluster config](https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/deploy/SparkSubmit.scala#L170) and does not propagate this to SparkContext.
In cluster mode, SparkSubmit passes this flag to `org.apache.spark.deploy.yarn.Client`, which only uses it for the [YARN ResourceManager](https://github.com/apache/spark/blob/master/yarn/stable/src/main/scala/org/apache/spark/deploy/yarn/Client.scala#L80), but does not propagate this to SparkContext.
This PR ensures that `spark.app.name` is always set if SparkSubmit receives the `--name` flag, which is what the usage promises. This makes it possible for applications to start a SparkContext with an empty conf `val sc = new SparkContext(new SparkConf)`, and inherit the app name from SparkSubmit.
Tested both modes on a YARN cluster.
Author: Andrew Or <andrewor14@gmail.com>
Closes#699 from andrewor14/yarn-app-name and squashes the following commits:
98f6a79 [Andrew Or] Fix tests
dea932f [Andrew Or] Merge branch 'master' of github.com:apache/spark into yarn-app-name
c86d9ca [Andrew Or] Respect SparkSubmit --name on YARN
It makes little sense to start a TaskContext that is interrupted. Indeed, I searched for all use cases of it and didn't find a single instance in which `interrupted` is true on construction.
This was inspired by reviewing #640, which adds an additional `@volatile var completed` that is similar. These are not the most urgent changes, but I wanted to push them out before I forget.
Author: Andrew Or <andrewor14@gmail.com>
Closes#675 from andrewor14/task-context and squashes the following commits:
9575e02 [Andrew Or] Add space
69455d1 [Andrew Or] Merge branch 'master' of github.com:apache/spark into task-context
c471490 [Andrew Or] Oops, removed one flag too many. Adding it back.
85311f8 [Andrew Or] Move interrupted flag from TaskContext constructor
This PR updates spark-submit to allow submitting Python scripts (currently only with deploy-mode=client, but that's all that was supported before) and updates the PySpark code to properly find various paths, etc. One significant change is that we assume we can always find the Python files either from the Spark assembly JAR (which will happen with the Maven assembly build in make-distribution.sh) or from SPARK_HOME (which will exist in local mode even if you use sbt assembly, and should be enough for testing). This means we no longer need a weird hack to modify the environment for YARN.
This patch also updates the Python worker manager to run python with -u, which means unbuffered output (send it to our logs right away instead of waiting a while after stuff was written); this should simplify debugging.
In addition, it fixes https://issues.apache.org/jira/browse/SPARK-1709, setting the main class from a JAR's Main-Class attribute if not specified by the user, and fixes a few help strings and style issues in spark-submit.
In the future we may want to make the `pyspark` shell use spark-submit as well, but it seems unnecessary for 1.0.
Author: Matei Zaharia <matei@databricks.com>
Closes#664 from mateiz/py-submit and squashes the following commits:
15e9669 [Matei Zaharia] Fix some uses of path.separator property
051278c [Matei Zaharia] Small style fixes
0afe886 [Matei Zaharia] Add license headers
4650412 [Matei Zaharia] Add pyFiles to PYTHONPATH in executors, remove old YARN stuff, add tests
15f8e1e [Matei Zaharia] Set PYTHONPATH in PythonWorkerFactory in case it wasn't set from outside
47c0655 [Matei Zaharia] More work to make spark-submit work with Python:
d4375bd [Matei Zaharia] Clean up description of spark-submit args a bit and add Python ones
Modifications to Spark core are limited to exposing functionality to test files + minor style fixes.
(728 / 769 lines are from tests)
Author: Andrew Or <andrewor14@gmail.com>
Closes#591 from andrewor14/event-log-tests and squashes the following commits:
2883837 [Andrew Or] Merge branch 'master' of github.com:apache/spark into event-log-tests
c3afcea [Andrew Or] Compromise
2d5daf8 [Andrew Or] Use temp directory provided by the OS rather than /tmp
2b52151 [Andrew Or] Remove unnecessary file delete + add a comment
62010fd [Andrew Or] More cleanup (renaming variables, updating comments etc)
ad2beff [Andrew Or] Clean up EventLoggingListenerSuite + modify a few comments
862e752 [Andrew Or] Merge branch 'master' of github.com:apache/spark into event-log-tests
e0ba2f8 [Andrew Or] Fix test failures caused by race condition in processing/mutating events
b990453 [Andrew Or] ReplayListenerBus suite - tests do not all pass yet
ab66a84 [Andrew Or] Tests for FileLogger + delete file after tests
187bb25 [Andrew Or] Formatting and renaming variables
769336f [Andrew Or] Merge branch 'master' of github.com:apache/spark into event-log-tests
5d38ffe [Andrew Or] Clean up EventLoggingListenerSuite + add comments
e12f4b1 [Andrew Or] Preliminary tests for EventLoggingListener (need major cleanup)
Author: witgo <witgo@qq.com>
Closes#423 from witgo/zipWithIndex and squashes the following commits:
039ec04 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
24d74c9 [witgo] review commit
763a5e4 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
59747d1 [witgo] review commit
7bf4d06 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
daa8f84 [witgo] review commit
4070613 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
18e6c97 [witgo] java api zipWithIndex test
11e2e7f [witgo] add zipWithIndex zipWithUniqueId methods to java api
This is a straightforward fix.
Author: Patrick Wendell <pwendell@gmail.com>
This patch had conflicts when merged, resolved by
Committer: Patrick Wendell <pwendell@gmail.com>
Closes#578 from pwendell/spark-submit-yarn and squashes the following commits:
96027c7 [Patrick Wendell] Test fixes
b5be173 [Patrick Wendell] Review feedback
4ac9cac [Patrick Wendell] SPARK-1652: spark-submit for yarn prints warnings even though calling as expected
This includes some minor code clean-up as well. The main change is that small files are not memory mapped. There is a nicer way to write that code block using Scala's `Try` but to make it easy to back port and as simple as possible, I opted for the more explicit but less pretty format.
Author: Patrick Wendell <pwendell@gmail.com>
Closes#43 from pwendell/block-iter-logging and squashes the following commits:
1cff512 [Patrick Wendell] Small issue from merge.
49f6c269 [Patrick Wendell] Merge remote-tracking branch 'apache/master' into block-iter-logging
4943351 [Patrick Wendell] Added a test and feedback on mateis review
a637a18 [Patrick Wendell] Review feedback and adding rewind() when reading byte buffers.
b76b95f [Patrick Wendell] Review feedback
4e1514e [Patrick Wendell] Don't memory map for small files
d238b88 [Patrick Wendell] Some logging and clean-up
This modifies spark-submit to do something more like the Hadoop `jar`
command. Now we have the following syntax:
./bin/spark-submit [options] user.jar [user options]
Author: Patrick Wendell <pwendell@gmail.com>
Closes#563 from pwendell/spark-submit and squashes the following commits:
32241fc [Patrick Wendell] Review feedback
3adfb69 [Patrick Wendell] Small fix
bc48139 [Patrick Wendell] SPARK-1606: Infer user application arguments instead of requiring --arg.
https://spark-project.atlassian.net/browse/SPARK-1235
In the current implementation, the running job will hang if the DAGScheduler crashes for some reason (eventProcessActor throws exception in receive() )
The reason is that the actor will automatically restart when the exception is thrown during the running but is not captured properly (Akka behaviour), and the JobWaiters are still waiting there for the completion of the tasks
In this patch, I refactored the DAGScheduler with Akka and manage the eventProcessActor with supervisor, so that upon the failure of a eventProcessActor, the supervisor will terminate the EventProcessActor and close the SparkContext
thanks for @kayousterhout and @markhamstra to give the hints in JIRA
Author: CodingCat <zhunansjtu@gmail.com>
Author: Xiangrui Meng <meng@databricks.com>
Author: Nan Zhu <CodingCat@users.noreply.github.com>
Closes#186 from CodingCat/SPARK-1235 and squashes the following commits:
a7fb0ee [CodingCat] throw Exception on failure of creating DAG
124d82d [CodingCat] blocking the constructor until event actor is ready
baf2d38 [CodingCat] fix the issue brought by non-blocking actorOf
35c886a [CodingCat] fix bug
82d08b3 [CodingCat] calling actorOf on system to ensure it is blocking
310a579 [CodingCat] style fix
cd02d9a [Nan Zhu] small fix
561cfbc [CodingCat] recover doCheckpoint
c048d0e [CodingCat] call submitWaitingStages for every event
a9eea039 [CodingCat] address Matei's comments
ac878ab [CodingCat] typo fix
5d1636a [CodingCat] re-trigger the test.....
9dfb033 [CodingCat] remove unnecessary changes
a7a2a97 [CodingCat] add StageCancelled message
fdf3b17 [CodingCat] just to retrigger the test......
089bc2f [CodingCat] address andrew's comments
228f4b0 [CodingCat] address comments from Mark
b68c1c7 [CodingCat] refactor DAGScheduler with Akka
810efd8 [Xiangrui Meng] akka solution
Unfortunately, this is not exhaustive - particularly hive tests still fail due to path issues.
Author: Mridul Muralidharan <mridulm80@apache.org>
This patch had conflicts when merged, resolved by
Committer: Matei Zaharia <matei@databricks.com>
Closes#505 from mridulm/windows_fixes and squashes the following commits:
ef12283 [Mridul Muralidharan] Move to org.apache.commons.lang3 for StringEscapeUtils. Earlier version was buggy appparently
cdae406 [Mridul Muralidharan] Remove leaked changes from > 2G fix branch
3267f4b [Mridul Muralidharan] Fix build failures
35b277a [Mridul Muralidharan] Fix Scalastyle failures
bc69d14 [Mridul Muralidharan] Change from hardcoded path separator
10c4d78 [Mridul Muralidharan] Use explicit encoding while using getBytes
1337abd [Mridul Muralidharan] fix classpath while running in windows
Original poster is @zsxwing, who reported this bug in #516.
Much of SparkListenerSuite relies on LiveListenerBus's `waitUntilEmpty()` method. As the name suggests, this waits until the event queue is empty. However, the following race condition could happen:
(1) We dequeue an event
(2) The queue is empty, we return true (even though the event has not been processed)
(3) The test asserts something assuming that all listeners have finished executing (and fails)
(4) The listeners receive and process the event
This PR makes (1) and (4) atomic by synchronizing around it. To do that, however, we must avoid using `eventQueue.take`, which is blocking and will cause a deadlock if we synchronize around it. As a workaround, we use the non-blocking `eventQueue.poll` + a semaphore to provide the same semantics.
This has been a possible race condition for a long time, but for some reason we've never run into it.
Author: Andrew Or <andrewor14@gmail.com>
Closes#544 from andrewor14/stage-info-test-fix and squashes the following commits:
3cbe40c [Andrew Or] Merge github.com:apache/spark into stage-info-test-fix
56dbbcb [Andrew Or] Check if event is actually added before releasing semaphore
eb486ae [Andrew Or] Synchronize accesses to the LiveListenerBus' event queue
This allows the view acls set by the user to be enforced by the history server. It also fixes filters being applied properly.
Author: Thomas Graves <tgraves@apache.org>
Closes#509 from tgravescs/SPARK-1489 and squashes the following commits:
869c186 [Thomas Graves] change to either acls enabled or disabled
0d8333c [Thomas Graves] Add history ui policy to allow acls to either use application set, history server force acls on, or off
65148b5 [Thomas Graves] SPARK-1489 Fix the HistoryServer view acls
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
This should go into 1.0 since it would return wrong data when the bug happens (which is pretty likely if cancellation is used). Test case attached.
1. Do not put partially executed partitions into cache (in task killing).
2. Iterator returned by CacheManager#getOrCompute was not an InterruptibleIterator, and was thus leading to uninterruptible jobs.
Thanks @aarondav and @ahirreddy for reporting and helping debug.
Author: Reynold Xin <rxin@apache.org>
Closes#521 from rxin/kill and squashes the following commits:
401033f [Reynold Xin] Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/spark into kill
7a7bdd2 [Reynold Xin] Add a new line in the end of JobCancellationSuite.scala.
35cd9f7 [Reynold Xin] Fixed a bug that partially executed partitions can be put into cache (in task killing).
mvn test fails (intermittently) due to thread leak - since scalatest runs all tests in same vm.
Author: Mridul Muralidharan <mridulm80@apache.org>
Closes#504 from mridulm/resource_leak_fixes and squashes the following commits:
a5d10d0 [Mridul Muralidharan] Prevent thread leaks while running tests : cleanup all threads when SparkContext.stop is invoked. Causes tests to fail
7b5e19c [Mridul Muralidharan] Prevent NPE while running tests
Also adds a unit test.
Author: Aaron Davidson <aaron@databricks.com>
Closes#522 from aarondav/cancel2 and squashes the following commits:
565c253 [Aaron Davidson] Update Java api for setJobGroup with interruptOnCancel
65b33d8 [Aaron Davidson] Add unit test for Thread interruption on cancellation
The two modified tests may fail if the race condition does not bid in our favor...
Author: Andrew Or <andrewor14@gmail.com>
Closes#516 from andrewor14/stage-info-test-fix and squashes the following commits:
b4b6100 [Andrew Or] Add/replace missing waitUntilEmpty() calls to listener bus
In https://issues.apache.org/jira/browse/SPARK-1540 we'd like to look at Spark's API to see if we can take advantage of Comparable keys in more places, which will make external spilling more efficient. This PR is a first step towards that that shows how to pass an Ordering when available and still continue functioning otherwise. It does this using a new implicit parameter with a default value of null.
The API is currently only in Scala -- in Java we'd have to add new versions of mapToPair and such that take a Comparator, or a new method to add a "type hint" to an RDD. We can address those later though.
Unfortunately requiring all keys to be Comparable would not work without requiring RDDs in general to contain only Comparable types. The reason is that methods such as distinct() and intersection() do a shuffle, but should be usable on RDDs of any type. So ordering will have to remain an optimization for the types that can be ordered. I think this isn't a horrible outcome though because one of the nice things about Spark's API is that it works on objects of *any* type, without requiring you to specify a schema or implement Writable or stuff like that.
Author: Matei Zaharia <matei@databricks.com>
This patch had conflicts when merged, resolved by
Committer: Reynold Xin <rxin@apache.org>
Closes#487 from mateiz/ordered-keys and squashes the following commits:
bd565f6 [Matei Zaharia] Pass an Ordering to only one version of groupBy because the Scala language spec doesn't allow having an optional parameter on all of them (this was only compiling in Scala 2.10 due to a bug).
4629965 [Matei Zaharia] Add tests for other versions of groupBy
3beae85 [Matei Zaharia] Added a test for implicit orderings
80b7a3b [Matei Zaharia] Add an optional Ordering parameter to PairRDDFunctions.
Sometimes executor threads are blocked waiting for IO or monitors, and the current implementation of job cancellation may never recover these threads. By simply invoking Thread.interrupt() during cancellation, we can often safely unblock the threads and use them for subsequent work.
Note that this feature must remain optional for now because of a bug in HDFS where Thread.interrupt() may cause nodes to be marked as permanently dead (as the InterruptedException is reinterpreted as an IOException during communication with some node).
Author: Aaron Davidson <aaron@databricks.com>
Closes#498 from aarondav/cancel and squashes the following commits:
e52b829 [Aaron Davidson] Don't use job.properties when null
82f78bb [Aaron Davidson] Update DAGSchedulerSuite
b67f472 [Aaron Davidson] Add comment on why interruptOnCancel is in setJobGroup
4cb9fd6 [Aaron Davidson] SPARK-1582 Invoke Thread.interrupt() when cancelling jobs
Even if users use `--arg`, `SparkSubmit` still uses `--args` for child args internally, which triggers a warning message that may confuse users:
~~~
--args is deprecated. Use --arg instead.
~~~
@sryza Does it look good to you?
Author: Xiangrui Meng <meng@databricks.com>
Closes#485 from mengxr/submit-arg and squashes the following commits:
5e1b9fe [Xiangrui Meng] update test
cebbeb7 [Xiangrui Meng] use --arg instead of --args in SparkSubmit to avoid warning messages
**Bug**: After the following command `sc.parallelize(1 to 1000).persist.map(_ + 1).count()` is run, the the persisted RDD is missing from the storage tab of the SparkUI.
**Cause**: The command creates two RDDs in one stage, a `ParallelCollectionRDD` and a `MappedRDD`. However, the existing StageInfo only keeps the RDDInfo of the last RDD associated with the stage (`MappedRDD`), and so all RDD information regarding the first RDD (`ParallelCollectionRDD`) is discarded. In this case, we persist the first RDD, but the StorageTab doesn't know about this RDD because it is not encoded in the StageInfo.
**Fix**: Record information of all RDDs in StageInfo, instead of just the last RDD (i.e. `stage.rdd`). Since stage boundaries are marked by shuffle dependencies, the solution is to traverse the last RDD's dependency tree, visiting only ancestor RDDs related through a sequence of narrow dependencies.
---
This PR also moves RDDInfo to its own file, includes a few style fixes, and adds a unit test for constructing StageInfos.
Author: Andrew Or <andrewor14@gmail.com>
Closes#469 from andrewor14/storage-ui-fix and squashes the following commits:
07fc7f0 [Andrew Or] Add back comment that was accidentally removed (minor)
5d799fe [Andrew Or] Add comment to justify testing of getNarrowAncestors with cycles
9d0e2b8 [Andrew Or] Hide details of getNarrowAncestors from outsiders
d2bac8a [Andrew Or] Deal with cycles in RDD dependency graph + add extensive tests
2acb177 [Andrew Or] Move getNarrowAncestors to RDD.scala
bfe83f0 [Andrew Or] Backtrace RDD dependency tree to find all RDDs that belong to a Stage
#446 faced a connection refused exception from these tests, causing them to timeout and fail after a long time. For now, let's disable these tests.
(We recently disabled the corresponding test in streaming in 7863ecca35. These tests are very similar).
Author: Andrew Or <andrewor14@gmail.com>
Closes#466 from andrewor14/ignore-ui-tests and squashes the following commits:
6f5a362 [Andrew Or] Ignore org.apache.spark.ui.UISuite tests
Over time as we've added more deployment modes, this have gotten a bit unwieldy with user-facing configuration options in Spark. Going forward we'll advise all users to run `spark-submit` to launch applications. This is a WIP patch but it makes the following improvements:
1. Improved `spark-env.sh.template` which was missing a lot of things users now set in that file.
2. Removes the shipping of SPARK_CLASSPATH, SPARK_JAVA_OPTS, and SPARK_LIBRARY_PATH to the executors on the cluster. This was an ugly hack. Instead it introduces config variables spark.executor.extraJavaOpts, spark.executor.extraLibraryPath, and spark.executor.extraClassPath.
3. Adds ability to set these same variables for the driver using `spark-submit`.
4. Allows you to load system properties from a `spark-defaults.conf` file when running `spark-submit`. This will allow setting both SparkConf options and other system properties utilized by `spark-submit`.
5. Made `SPARK_LOCAL_IP` an environment variable rather than a SparkConf property. This is more consistent with it being set on each node.
Author: Patrick Wendell <pwendell@gmail.com>
Closes#299 from pwendell/config-cleanup and squashes the following commits:
127f301 [Patrick Wendell] Improvements to testing
a006464 [Patrick Wendell] Moving properties file template.
b4b496c [Patrick Wendell] spark-defaults.properties -> spark-defaults.conf
0086939 [Patrick Wendell] Minor style fixes
af09e3e [Patrick Wendell] Mention config file in docs and clean-up docs
b16e6a2 [Patrick Wendell] Cleanup of spark-submit script and Scala quick start guide
af0adf7 [Patrick Wendell] Automatically add user jar
a56b125 [Patrick Wendell] Responses to Tom's review
d50c388 [Patrick Wendell] Merge remote-tracking branch 'apache/master' into config-cleanup
a762901 [Patrick Wendell] Fixing test failures
ffa00fe [Patrick Wendell] Review feedback
fda0301 [Patrick Wendell] Note
308f1f6 [Patrick Wendell] Properly escape quotes and other clean-up for YARN
e83cd8f [Patrick Wendell] Changes to allow re-use of test applications
be42f35 [Patrick Wendell] Handle case where SPARK_HOME is not set
c2a2909 [Patrick Wendell] Test compile fixes
4ee6f9d [Patrick Wendell] Making YARN doc changes consistent
afc9ed8 [Patrick Wendell] Cleaning up line limits and two compile errors.
b08893b [Patrick Wendell] Additional improvements.
ace4ead [Patrick Wendell] Responses to review feedback.
b72d183 [Patrick Wendell] Review feedback for spark env file
46555c1 [Patrick Wendell] Review feedback and import clean-ups
437aed1 [Patrick Wendell] Small fix
761ebcd [Patrick Wendell] Library path and classpath for drivers
7cc70e4 [Patrick Wendell] Clean up terminology inside of spark-env script
5b0ba8e [Patrick Wendell] Don't ship executor envs
84cc5e5 [Patrick Wendell] Small clean-up
1f75238 [Patrick Wendell] SPARK_JAVA_OPTS --> SPARK_MASTER_OPTS for master settings
4982331 [Patrick Wendell] Remove SPARK_LIBRARY_PATH
6eaf7d0 [Patrick Wendell] executorJavaOpts
0faa3b6 [Patrick Wendell] Stash of adding config options in submit script and YARN
ac2d65e [Patrick Wendell] Change spark.local.dir -> SPARK_LOCAL_DIRS
Author: Kan Zhang <kzhang@apache.org>
Closes#401 from kanzhang/fix-1475 and squashes the following commits:
c6058bd [Kan Zhang] Fixing a race condition in event listener unit test
Author: Holden Karau <holden@pigscanfly.ca>
Closes#18 from holdenk/addkfoldcrossvalidation and squashes the following commits:
208db9b [Holden Karau] Fix a bad space
e84f2fc [Holden Karau] Fix the test, we should be looking at the second element instead
6ddbf05 [Holden Karau] swap training and validation order
7157ae9 [Holden Karau] CR feedback
90896c7 [Holden Karau] New line
150889c [Holden Karau] Fix up error messages in the MLUtilsSuite
2cb90b3 [Holden Karau] Fix the names in kFold
c702a96 [Holden Karau] Fix imports in MLUtils
e187e35 [Holden Karau] Move { up to same line as whenExecuting(random) in RandomSamplerSuite.scala
c5b723f [Holden Karau] clean up
7ebe4d5 [Holden Karau] CR feedback, remove unecessary learners (came back during merge mistake) and insert an empty line
bb5fa56 [Holden Karau] extra line sadness
163c5b1 [Holden Karau] code review feedback 1.to -> 1 to and folds -> numFolds
5a33f1d [Holden Karau] Code review follow up.
e8741a7 [Holden Karau] CR feedback
b78804e [Holden Karau] Remove cross validation [TODO in another pull request]
91eae64 [Holden Karau] Consolidate things in mlutils
264502a [Holden Karau] Add a test for the bug that was found with BernoulliSampler not copying the complement param
dd0b737 [Holden Karau] Wrap long lines (oops)
c0b7fa4 [Holden Karau] Switch FoldedRDD to use BernoulliSampler and PartitionwiseSampledRDD
08f8e4d [Holden Karau] Fix BernoulliSampler to respect complement
a751ec6 [Holden Karau] Add k-fold cross validation to MLLib
For your consideration: scalac currently notes a number of feature warnings during compilation:
```
[warn] there were 65 feature warning(s); re-run with -feature for details
```
Warnings are like:
```
[warn] /Users/srowen/Documents/spark/core/src/main/scala/org/apache/spark/SparkContext.scala:1261: implicit conversion method rddToPairRDDFunctions should be enabled
[warn] by making the implicit value scala.language.implicitConversions visible.
[warn] This can be achieved by adding the import clause 'import scala.language.implicitConversions'
[warn] or by setting the compiler option -language:implicitConversions.
[warn] See the Scala docs for value scala.language.implicitConversions for a discussion
[warn] why the feature should be explicitly enabled.
[warn] implicit def rddToPairRDDFunctions[K: ClassTag, V: ClassTag](rdd: RDD[(K, V)]) =
[warn] ^
```
scalac is suggesting that it's just best practice to explicitly enable certain language features by importing them where used.
This PR simply adds the imports it suggests (and squashes one other Java warning along the way). This leaves just deprecation warnings in the build.
Author: Sean Owen <sowen@cloudera.com>
Closes#404 from srowen/SPARK-1488 and squashes the following commits:
8598980 [Sean Owen] Quiet scalac warnings about language features by explicitly importing language features.
39bc831 [Sean Owen] Enable -feature in scalac to emit language feature warnings
JIRA issue [here](https://issues.apache.org/jira/browse/SPARK-1415).
New Hadoop API of `InputFormat` does not provide the `minSplits` parameter, which makes the API incompatible between `HadoopRDD` and `NewHadoopRDD`. The PR is for constructing compatible APIs.
Though `minSplits` is deprecated by New Hadoop API, we think it is better to make APIs compatible here.
**Note** that `minSplits` in `wholeTextFiles` could only be treated as a *suggestion*, the real number of splits may not be greater than `minSplits` due to `isSplitable()=false`.
Author: Xusen Yin <yinxusen@gmail.com>
Closes#376 from yinxusen/hadoop-min-split and squashes the following commits:
76417f6 [Xusen Yin] refine comments
c10af60 [Xusen Yin] refine comments and rewrite new class for wholeTextFile
766d05b [Xusen Yin] refine Java API and comments
4875755 [Xusen Yin] add minSplits for WholeTextFiles
The Spark codebase is a bit fast-and-loose when accessing classloaders and this has caused a few bugs to surface in master.
This patch defines some utility methods for accessing classloaders. This makes the intention when accessing a classloader much more explicit in the code and fixes a few cases where the wrong one was chosen.
case (a) -> We want the classloader that loaded Spark
case (b) -> We want the context class loader, or if not present, we want (a)
This patch provides a better fix for SPARK-1403 (https://issues.apache.org/jira/browse/SPARK-1403) than the current work around, which it reverts. It also fixes a previously unreported bug that the `./spark-submit` script did not work for running with `local` master. It didn't work because the executor classloader did not properly delegate to the context class loader (if it is defined) and in local mode the context class loader is set by the `./spark-submit` script. A unit test is added for that case.
Author: Patrick Wendell <pwendell@gmail.com>
Closes#398 from pwendell/class-loaders and squashes the following commits:
b4a1a58 [Patrick Wendell] Minor clean up
14f1272 [Patrick Wendell] SPARK-1480: Clean up use of classloaders
When debugging Spark Streaming applications it is necessary to monitor certain metrics that are not shown in the Spark application UI. For example, what is average processing time of batches? What is the scheduling delay? Is the system able to process as fast as it is receiving data? How many records I am receiving through my receivers?
While the StreamingListener interface introduced in the 0.9 provided some of this information, it could only be accessed programmatically. A UI that shows information specific to the streaming applications is necessary for easier debugging. This PR introduces such a UI. It shows various statistics related to the streaming application. Here is a screenshot of the UI running on my local machine.
http://i.imgur.com/1ooDGhm.png
This UI is integrated into the Spark UI running at 4040.
Author: Tathagata Das <tathagata.das1565@gmail.com>
Author: Andrew Or <andrewor14@gmail.com>
Closes#290 from tdas/streaming-web-ui and squashes the following commits:
fc73ca5 [Tathagata Das] Merge pull request #9 from andrewor14/ui-refactor
642dd88 [Andrew Or] Merge SparkUISuite.scala into UISuite.scala
eb30517 [Andrew Or] Merge github.com:apache/spark into ui-refactor
f4f4cbe [Tathagata Das] More minor fixes.
34bb364 [Tathagata Das] Merge branch 'streaming-web-ui' of github.com:tdas/spark into streaming-web-ui
252c566 [Tathagata Das] Merge pull request #8 from andrewor14/ui-refactor
e038b4b [Tathagata Das] Addressed Patrick's comments.
125a054 [Andrew Or] Disable serving static resources with gzip
90feb8d [Andrew Or] Address Patrick's comments
89dae36 [Tathagata Das] Merge branch 'streaming-web-ui' of github.com:tdas/spark into streaming-web-ui
72fe256 [Tathagata Das] Merge pull request #6 from andrewor14/ui-refactor
2fc09c8 [Tathagata Das] Added binary check exclusions
aa396d4 [Andrew Or] Rename tabs and pages (No more IndexPage.scala)
f8e1053 [Tathagata Das] Added Spark and Streaming UI unit tests.
caa5e05 [Tathagata Das] Merge branch 'streaming-web-ui' of github.com:tdas/spark into streaming-web-ui
585cd65 [Tathagata Das] Merge pull request #5 from andrewor14/ui-refactor
914b8ff [Tathagata Das] Moved utils functions to UIUtils.
548c98c [Andrew Or] Wide refactoring of WebUI, UITab, and UIPage (see commit message)
6de06b0 [Tathagata Das] Merge remote-tracking branch 'apache/master' into streaming-web-ui
ee6543f [Tathagata Das] Minor changes based on Andrew's comments.
fa760fe [Tathagata Das] Fixed long line.
1c0bcef [Tathagata Das] Refactored streaming UI into two files.
1af239b [Tathagata Das] Changed streaming UI to attach itself as a tab with the Spark UI.
827e81a [Tathagata Das] Merge branch 'streaming-web-ui' of github.com:tdas/spark into streaming-web-ui
168fe86 [Tathagata Das] Merge pull request #2 from andrewor14/ui-refactor
3e986f8 [Tathagata Das] Merge remote-tracking branch 'apache/master' into streaming-web-ui
c78c92d [Andrew Or] Remove outdated comment
8f7323b [Andrew Or] End of file new lines, indentation, and imports (minor)
0d61ee8 [Andrew Or] Merge branch 'streaming-web-ui' of github.com:tdas/spark into ui-refactor
9a48fa1 [Andrew Or] Allow adding tabs to SparkUI dynamically + add example
61358e3 [Tathagata Das] Merge remote-tracking branch 'apache-github/master' into streaming-web-ui
53be2c5 [Tathagata Das] Minor style updates.
ed25dfc [Andrew Or] Generalize SparkUI header to display tabs dynamically
a37ad4f [Andrew Or] Comments, imports and formatting (minor)
cd000b0 [Andrew Or] Merge github.com:apache/spark into ui-refactor
7d57444 [Andrew Or] Refactoring the UI interface to add flexibility
aef4dd5 [Tathagata Das] Added Apache licenses.
db27bad [Tathagata Das] Added last batch processing time to StreamingUI.
4d86e98 [Tathagata Das] Added basic stats to the StreamingUI and refactored the UI to a Page to make it easier to transition to using SparkUI later.
93f1c69 [Tathagata Das] Added network receiver information to the Streaming UI.
56cc7fb [Tathagata Das] First cut implementation of Streaming UI.
Make coalesce test deterministic by setting pre-defined seeds. (Saw random failures in other PRs.)
Author: Xiangrui Meng <meng@databricks.com>
Closes#387 from mengxr/fix-random and squashes the following commits:
59bc16f [Xiangrui Meng] make coalesce test deterministic in RDDSuite
Author: Thomas Graves <tgraves@apache.org>
Closes#344 from tgravescs/SPARK-1417 and squashes the following commits:
c450b5f [Thomas Graves] fix test
e1c1d7e [Thomas Graves] add missing $ to appUIAddress
e982ddb [Thomas Graves] use appUIHostPort in appUIAddress
0803ec2 [Thomas Graves] Review comment updates - remove extra newline, simplify assert in test
658a8ec [Thomas Graves] Add a appUIHostPort routine
0614208 [Thomas Graves] Fix test
2a6b1b7 [Thomas Graves] SPARK-1417: Spark on Yarn - spark UI link from resourcemanager is broken
Author: Sundeep Narravula <sundeepn@superduel.local>
Author: Sundeep Narravula <sundeepn@dhcpx-204-110.corp.yahoo.com>
Closes#246 from sundeepn/uikilljob and squashes the following commits:
5fdd0e2 [Sundeep Narravula] Fix test string
f6fdff1 [Sundeep Narravula] Format fix; reduced line size to less than 100 chars
d1daeb9 [Sundeep Narravula] Incorporating review comments.
8d97923 [Sundeep Narravula] Ability to kill jobs thru the UI. This behavior can be turned on be settings the following variable: spark.ui.killEnabled=true (default=false) Adding DAGScheduler event StageCancelled and corresponding handlers. Added cancellation reason to handlers.
stack these together in a commit else they show up chunk by chunk in different commits.
Author: Sandeep <sandeep@techaddict.me>
Closes#380 from techaddict/white_space and squashes the following commits:
b58f294 [Sandeep] Remove Unnecessary Whitespace's
The new feature of event logging, introduced in #42, allows the user to persist the details of his/her Spark application to storage, and later replay these events to reconstruct an after-the-fact SparkUI.
Currently, however, a persisted UI can only be rendered through the standalone Master. This greatly limits the use case of this new feature as many people also run Spark on Yarn / Mesos.
This PR introduces a new entity called the HistoryServer, which, given a log directory, keeps track of all completed applications independently of a Spark Master. Unlike Master, the HistoryServer needs not be running while the application is still running. It is relatively light-weight in that it only maintains static information of applications and performs no scheduling.
To quickly test it out, generate event logs with ```spark.eventLog.enabled=true``` and run ```sbin/start-history-server.sh <log-dir-path>```. Your HistoryServer awaits on port 18080.
Comments and feedback are most welcome.
---
A few other changes introduced in this PR include refactoring the WebUI interface, which is beginning to have a lot of duplicate code now that we have added more functionality to it. Two new SparkListenerEvents have been introduced (SparkListenerApplicationStart/End) to keep track of application name and start/finish times. This PR also clarifies the semantics of the ReplayListenerBus introduced in #42.
A potential TODO in the future (not part of this PR) is to render live applications in addition to just completed applications. This is useful when applications fail, a condition that our current HistoryServer does not handle unless the user manually signals application completion (by creating the APPLICATION_COMPLETION file). Handling live applications becomes significantly more challenging, however, because it is now necessary to render the same SparkUI multiple times. To avoid reading the entire log every time, which is inefficient, we must handle reading the log from where we previously left off, but this becomes fairly complicated because we must deal with the arbitrary behavior of each input stream.
Author: Andrew Or <andrewor14@gmail.com>
Closes#204 from andrewor14/master and squashes the following commits:
7b7234c [Andrew Or] Finished -> Completed
b158d98 [Andrew Or] Address Patrick's comments
69d1b41 [Andrew Or] Do not block on posting SparkListenerApplicationEnd
19d5dd0 [Andrew Or] Merge github.com:apache/spark
f7f5bf0 [Andrew Or] Make history server's web UI port a Spark configuration
2dfb494 [Andrew Or] Decouple checking for application completion from replaying
d02dbaa [Andrew Or] Expose Spark version and include it in event logs
2282300 [Andrew Or] Add documentation for the HistoryServer
567474a [Andrew Or] Merge github.com:apache/spark
6edf052 [Andrew Or] Merge github.com:apache/spark
19e1fb4 [Andrew Or] Address Thomas' comments
248cb3d [Andrew Or] Limit number of live applications + add configurability
a3598de [Andrew Or] Do not close file system with ReplayBus + fix bind address
bc46fc8 [Andrew Or] Merge github.com:apache/spark
e2f4ff9 [Andrew Or] Merge github.com:apache/spark
050419e [Andrew Or] Merge github.com:apache/spark
81b568b [Andrew Or] Fix strange error messages...
0670743 [Andrew Or] Decouple page rendering from loading files from disk
1b2f391 [Andrew Or] Minor changes
a9eae7e [Andrew Or] Merge branch 'master' of github.com:apache/spark
d5154da [Andrew Or] Styling and comments
5dbfbb4 [Andrew Or] Merge branch 'master' of github.com:apache/spark
60bc6d5 [Andrew Or] First complete implementation of HistoryServer (only for finished apps)
7584418 [Andrew Or] Report application start/end times to HistoryServer
8aac163 [Andrew Or] Add basic application table
c086bd5 [Andrew Or] Add HistoryServer and scripts ++ Refactor WebUI interface
[SPARK-729](https://spark-project.atlassian.net/browse/SPARK-729) concerns when free variables in closure arguments to transformations are captured. Currently, it is possible for closures to get the environment in which they are serialized (not the environment in which they are created). There are a few possible approaches to solving this problem and this PR will discuss some of them. The approach I took has the advantage of being simple, obviously correct, and minimally-invasive, but it preserves something that has been bothering me about Spark's closure handling, so I'd like to discuss an alternative and get some feedback on whether or not it is worth pursuing.
## What I did
The basic approach I took depends on the work I did for #143, and so this PR is based atop that. Specifically: #143 modifies `ClosureCleaner.clean` to preemptively determine whether or not closures are serializable immediately upon closure cleaning (rather than waiting for an job involving that closure to be scheduled). Thus non-serializable closure exceptions will be triggered by the line defining the closure rather than triggered where the closure is used.
Since the easiest way to determine whether or not a closure is serializable is to attempt to serialize it, the code in #143 is creating a serialized closure as part of `ClosureCleaner.clean`. `clean` currently modifies its argument, but the method in `SparkContext` that wraps it to return a value (a reference to the modified-in-place argument). This branch modifies `ClosureCleaner.clean` so that it returns a value: if it is cleaning a serializable closure, it returns the result of deserializing its serialized argument; therefore it is returning a closure with an environment captured at cleaning time. `SparkContext.clean` then returns the result of `ClosureCleaner.clean`, rather than a reference to its modified-in-place argument.
I've added tests for this behavior (777a1bc). The pull request as it stands, given the changes in #143, is nearly trivial. There is some overhead from deserializing the closure, but it is minimal and the benefit of obvious operational correctness (vs. a more sophisticated but harder-to-validate transformation in `ClosureCleaner`) seems pretty important. I think this is a fine way to solve this problem, but it's not perfect.
## What we might want to do
The thing that has been bothering me about Spark's handling of closures is that it seems like we should be able to statically ensure that cleaning and serialization happen exactly once for a given closure. If we serialize a closure in order to determine whether or not it is serializable, we should be able to hang on to the generated byte buffer and use it instead of re-serializing the closure later. By replacing closures with instances of a sum type that encodes whether or not a closure has been cleaned or serialized, we could handle clean, to-be-cleaned, and serialized closures separately with case matches. Here's a somewhat-concrete sketch (taken from my git stash) of what this might look like:
```scala
package org.apache.spark.util
import java.nio.ByteBuffer
import scala.reflect.ClassManifest
sealed abstract class ClosureBox[T] { def func: T }
final case class RawClosure[T](func: T) extends ClosureBox[T] {}
final case class CleanedClosure[T](func: T) extends ClosureBox[T] {}
final case class SerializedClosure[T](func: T, bytebuf: ByteBuffer) extends ClosureBox[T] {}
object ClosureBoxImplicits {
implicit def closureBoxFromFunc[T <: AnyRef](fun: T) = new RawClosure[T](fun)
}
```
With these types declared, we'd be able to change `ClosureCleaner.clean` to take a `ClosureBox[T=>U]` (possibly generated by implicit conversion) and return a `ClosureBox[T=>U]` (either a `CleanedClosure[T=>U]` or a `SerializedClosure[T=>U]`, depending on whether or not serializability-checking was enabled) instead of a `T=>U`. A case match could thus short-circuit cleaning or serializing closures that had already been cleaned or serialized (both in `ClosureCleaner` and in the closure serializer). Cleaned-and-serialized closures would be represented by a boxed tuple of the original closure and a serialized copy (complete with an environment quiesced at transformation time). Additional implicit conversions could convert from `ClosureBox` instances to the underlying function type where appropriate. Tracking this sort of state in the type system seems like the right thing to do to me.
### Why we might not want to do that
_It's pretty invasive._ Every function type used by every `RDD` subclass would have to change to reflect that they expected a `ClosureBox[T=>U]` instead of a `T=>U`. This obscures what's going on and is not a little ugly. Although I really like the idea of using the type system to enforce the clean-or-serialize once discipline, it might not be worth adding another layer of types (even if we could hide some of the extra boilerplate with judicious application of implicit conversions).
_It statically guarantees a property whose absence is unlikely to cause any serious problems as it stands._ It appears that all closures are currently dynamically cleaned once and it's not obvious that repeated closure-cleaning is likely to be a problem in the future. Furthermore, serializing closures is relatively cheap, so doing it once to check for serialization and once again to actually ship them across the wire doesn't seem like a big deal.
Taken together, these seem like a high price to pay for statically guaranteeing that closures are operated upon only once.
## Other possibilities
I felt like the serialize-and-deserialize approach was best due to its obvious simplicity. But it would be possible to do a more sophisticated transformation within `ClosureCleaner.clean`. It might also be possible for `clean` to modify its argument in a way so that whether or not a given closure had been cleaned would be apparent upon inspection; this would buy us some of the operational benefits of the `ClosureBox` approach but not the static cleanliness.
I'm interested in any feedback or discussion on whether or not the problems with the type-based approach indeed outweigh the advantage, as well as of approaches to this issue and to closure handling in general.
Author: William Benton <willb@redhat.com>
Closes#189 from willb/spark-729 and squashes the following commits:
f4cafa0 [William Benton] Stylistic changes and cleanups
b3d9c86 [William Benton] Fixed style issues in tests
9b56ce0 [William Benton] Added array-element capture test
97e9d91 [William Benton] Split closure-serializability failure tests
12ef6e3 [William Benton] Skip proactive closure capture for runJob
8ee3ee7 [William Benton] Predictable closure environment capture
12c63a7 [William Benton] Added tests for variable capture in closures
d6e8dd6 [William Benton] Don't check serializability of DStream transforms.
4ecf841 [William Benton] Make proactive serializability checking optional.
d8df3db [William Benton] Adds proactive closure-serializablilty checking
21b4b06 [William Benton] Test cases for SPARK-897.
d5947b3 [William Benton] Ensure assertions in Graph.apply are asserted.
Author: Kan Zhang <kzhang@apache.org>
Closes#366 from kanzhang/SPARK-1407 and squashes the following commits:
cd0629f [Kan Zhang] code refactoring and adding test
b073ee6 [Kan Zhang] SPARK-1407 drain event queue before stopping event logger
