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https://issues.apache.org/jira/browse/DRILL-4278?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15103902#comment-15103902
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jean-claude commented on DRILL-4278:
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yes it is a heap issue, the old space keeps climbing up. I can run "jcmd pid 
GC.run" while it is executing queries and you can see the old pace going up and 
up until the query gets very long and eventually and OOM exception will occur. 

As stated if you don't use LIMIT the old space does not go up and up..

$ 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          
  

> 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, 1.5.0
>         Environment: OS X
> 0: jdbc:drill:zk=local> select * from sys.version;
> +----------+-------------------------------------------+-----------------------------------------------------+----------------------------+----------------------------+----------------------------+
> | version  |                 commit_id                 |                   
> commit_message                    |        commit_time         |        
> build_email         |         build_time         |
> +----------+-------------------------------------------+-----------------------------------------------------+----------------------------+----------------------------+----------------------------+
> | 1.4.0    | 32b871b24c7b69f59a1d2e70f444eed6e599e825  | 
> [maven-release-plugin] prepare release drill-1.4.0  | 08.12.2015 @ 00:24:59 
> PST  | venki.koruka...@gmail.com  | 08.12.2015 @ 01:14:39 PST  |
> +----------+-------------------------------------------+-----------------------------------------------------+----------------------------+----------------------------+----------------------------+
> 0: jdbc:drill:zk=local> select * from sys.options where status <> 'DEFAULT';
> +-----------------------------+-------+---------+----------+----------+-------------+-----------+------------+
> |            name             | kind  |  type   |  status  | num_val  | 
> string_val  | bool_val  | float_val  |
> +-----------------------------+-------+---------+----------+----------+-------------+-----------+------------+
> | planner.slice_target        | LONG  | SYSTEM  | CHANGED  | 10       | null  
>       | null      | null       |
> | planner.width.max_per_node  | LONG  | SYSTEM  | CHANGED  | 5        | null  
>       | null      | null       |
> +-----------------------------+-------+---------+----------+----------+-------------+-----------+------------+
> 2 rows selected (0.16 seconds)
>            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.
> I have used parquet files and CSV files. In either case the behaviour is the 
> same.



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