Repository: spark Updated Branches: refs/heads/master f9adda9af -> 73c8ea84a
[SPARK-4384] [PySpark] improve sort spilling If there some big broadcasts (or other object) in Python worker, the free memory could be used for sorting will be too small, then it will keep spilling small files into disks, finally failed with too many open files. This PR try to delay the spilling until the used memory goes over limit and start to increase since last spilling, it will increase the size of spilling files, improve the stability and performance in this cases. (We also do this in ExternalAggregator). Author: Davies Liu <[email protected]> Closes #3252 from davies/sort and squashes the following commits: 711fb6c [Davies Liu] improve sort spilling Project: http://git-wip-us.apache.org/repos/asf/spark/repo Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/73c8ea84 Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/73c8ea84 Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/73c8ea84 Branch: refs/heads/master Commit: 73c8ea84a668f443eb18ce15ba97023da041d808 Parents: f9adda9 Author: Davies Liu <[email protected]> Authored: Wed Nov 19 15:45:37 2014 -0800 Committer: Josh Rosen <[email protected]> Committed: Wed Nov 19 15:45:37 2014 -0800 ---------------------------------------------------------------------- python/pyspark/shuffle.py | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/spark/blob/73c8ea84/python/pyspark/shuffle.py ---------------------------------------------------------------------- diff --git a/python/pyspark/shuffle.py b/python/pyspark/shuffle.py index 5931e92..10a7ccd 100644 --- a/python/pyspark/shuffle.py +++ b/python/pyspark/shuffle.py @@ -478,13 +478,21 @@ class ExternalSorter(object): os.makedirs(d) return os.path.join(d, str(n)) + def _next_limit(self): + """ + Return the next memory limit. If the memory is not released + after spilling, it will dump the data only when the used memory + starts to increase. + """ + return max(self.memory_limit, get_used_memory() * 1.05) + def sorted(self, iterator, key=None, reverse=False): """ Sort the elements in iterator, do external sort when the memory goes above the limit. """ global MemoryBytesSpilled, DiskBytesSpilled - batch = 100 + batch, limit = 100, self._next_limit() chunks, current_chunk = [], [] iterator = iter(iterator) while True: @@ -504,6 +512,7 @@ class ExternalSorter(object): chunks.append(self.serializer.load_stream(open(path))) current_chunk = [] gc.collect() + limit = self._next_limit() MemoryBytesSpilled += (used_memory - get_used_memory()) << 20 DiskBytesSpilled += os.path.getsize(path) --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
