Unified daemon thread pools
As requested by @mateiz in an earlier pull request, this refactors various daemon thread pools to use a set of methods in utils.scala, and also changes the thread-pool-creation methods in utils.scala to use named thread pools for improved debugging.
Job killing
Moving https://github.com/mesos/spark/pull/935 here
The high level idea is to have an "interrupted" field in TaskContext, and a task should check that flag to determine if its execution should continue. For convenience, I provide an InterruptibleIterator which wraps around a normal iterator but checks for the interrupted flag. I also provide an InterruptibleRDD that wraps around an existing RDD.
As part of this pull request, I added an AsyncRDDActions class that provides a number of RDD actions that return a FutureJob (extending scala.concurrent.Future). The FutureJob can be used to kill the job execution, or waits until the job finishes.
This is NOT ready for merging yet. Remaining TODOs:
1. Add unit tests
2. Add job killing functionality for local scheduler (current job killing functionality only works in cluster scheduler)
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Update on Oct 10, 2013:
This is ready!
Related future work:
- Figure out how to handle the job triggered by RangePartitioner (this one is tough; might become future work)
- Java API
- Python API
Refactor BlockId into an actual type
Converts all of our BlockId strings into actual BlockId types. Here are some advantages of doing this now:
+ Type safety
+ Code clarity - it's now obvious what the key of a shuffle or rdd block is, for instance. Additionally, appearing in tuple/map type signatures is a big readability bonus. A Seq[(String, BlockStatus)] is not very clear. Further, we can now use more Scala features, like matching on BlockId types.
+ Explicit usage - we can now formally tell where various BlockIds are being used (without doing string searches); this makes updating current BlockIds a much clearer process, and compiler-supported.
(I'm looking at you, shuffle file consolidation.)
+ It will only get harder to make this change as time goes on.
Downside is, of course, that this is a very invasive change touching a lot of different files, which will inevitably lead to merge conflicts for many.
This is an unfortunately invasive change which converts all of our BlockId
strings into actual BlockId types. Here are some advantages of doing this now:
+ Type safety
+ Code clarity - it's now obvious what the key of a shuffle or rdd block is,
for instance. Additionally, appearing in tuple/map type signatures is a big
readability bonus. A Seq[(String, BlockStatus)] is not very clear.
Further, we can now use more Scala features, like matching on BlockId types.
+ Explicit usage - we can now formally tell where various BlockIds are being used
(without doing string searches); this makes updating current BlockIds a much
clearer process, and compiler-supported.
(I'm looking at you, shuffle file consolidation.)
+ It will only get harder to make this change as time goes on.
Since this touches a lot of files, it'd be best to either get this patch
in quickly or throw it on the ground to avoid too many secondary merge conflicts.
Add an optional closure parameter to HadoopRDD instantiation to use when creating local JobConfs.
Having HadoopRDD accept this optional closure eliminates the need for the HadoopFileRDD added earlier. It makes the HadoopRDD more general, in that the caller can specify any JobConf initialization flow.