jean-claude created DRILL-4278:
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Summary: Memory leak when using LIMIT
Key: DRILL-4278
URL: https://issues.apache.org/jira/browse/DRILL-4278
Project: Apache Drill
Issue Type: Bug
Components: Execution - RPC
Affects Versions: 1.4.0
Environment: OS X
Reporter: jean-claude
copy the parquet files in the samples directory so that you have a 12 or so
$ ls -lha /apache-drill-1.4.0/sample-data/nationsMF/
nationsMF1.parquet
nationsMF2.parquet
nationsMF3.parquet
create a file with a few thousand lines like these
select * from dfs.`/Users/jccote/apache-drill-1.4.0/sample-data/nationsMF`
limit 500;
start drill
$ /apache-drill-1.4.0/bin/drill-embeded
reduce the slice target size to force drill to use multiple fragment/threads
jdbc:drill:zk=local> system set planner.slice_target=10;
now run the list of queries from the file your created above
jdbc:drill:zk=local> !run /Users/jccote/test-memory-leak-using-limit.sql
the java heap space keeps going up until the old space is at 100% and
eventually you get an OutOfMemoryException in drill
$ jstat -gccause 86850 5s
S0 S1 E O M CCS YGC YGCT FGC FGCT GCT
LGCC GCC
0.00 0.00 100.00 100.00 98.56 96.71 2279 26.682 240 458.139
484.821 GCLocker Initiated GC Ergonomics
0.00 0.00 100.00 99.99 98.56 96.71 2279 26.682 242 461.347
488.028 Allocation Failure Ergonomics
0.00 0.00 100.00 99.99 98.56 96.71 2279 26.682 245 466.630
493.311 Allocation Failure Ergonomics
0.00 0.00 100.00 99.99 98.56 96.71 2279 26.682 247 470.020
496.702 Allocation Failure Ergonomics
If you do the same test but do not use the LIMIT then the memory usage does not
go up.
If you add a where clause so that no results are returned, then the memory
usage does not go up.
Something with the RPC layer?
Also it seems sensitive to the number of fragments/threads. If you limit it to
one fragment/thread the memory usage goes up much slower.
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