[jira] [Assigned] (DRILL-4823) Fix OOM while trying to prune partitions with reasonable data size

["Zelaine Fong (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DRILL-4823?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zelaine Fong reassigned DRILL-4823:
-----------------------------------

    Assignee: Boaz Ben-Zvi  (was: Arina Ielchiieva)

Assigning to [~ben-zvi] for code review.

> Fix OOM while trying to prune partitions with reasonable data size
> ------------------------------------------------------------------
>
>                 Key: DRILL-4823
>                 URL: https://issues.apache.org/jira/browse/DRILL-4823
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Functions - Drill, Query Planning & Optimization
>    Affects Versions: 1.6.0
>            Reporter: Arina Ielchiieva
>            Assignee: Boaz Ben-Zvi
>             Fix For: 1.9.0
>
>
> _Example query:_
> {code:sql}
> select  '/'||dir0||'/'||dir1||'/'||dir2||'/'||dir3 , count(*)
>   FROM dfs.`/path/to/parquet/files`
>   WHERE ('/'||dir0||'/'||dir1||'/'||dir2||'/'||dir3)  IN ( 
>   '/2015/11/30', 
>   '//2015/09/01',
>   '/2015/09/02', 
>   '/2015/09/03',
>   '/2015/09/04',
>   '/2015/09/09',  
>   '/2016/03/30'
>   )
>   group by   '/'||dir0||'/'||dir1||'/'||dir2||'/'||dir3
>   order by 1;
> {code}
> _Error:_
> OOM while trying to prune partitions:
> {noformat}
> org.apache.drill.exec.exception.OutOfMemoryException: Unable to allocate buffer of size 256 due to memory limit. Current allocation: 5242880
> 	at org.apache.drill.exec.memory.BaseAllocator.buffer(BaseAllocator.java:216) ~[drill-memory-base-1.6.0.jar:1.6.0]
> 	at org.apache.drill.exec.ops.BufferManagerImpl.getManagedBuffer(BufferManagerImpl.java:60) ~[drill-java-exec-1.6.0.jar:1.6.0]
> 	at org.apache.drill.exec.ops.BufferManagerImpl.getManagedBuffer(BufferManagerImpl.java:56) ~[drill-java-exec-1.6.0.jar:1.6.0]
> 	at org.apache.drill.exec.ops.QueryContext.getManagedBuffer(QueryContext.java:241) ~[drill-java-exec-1.6.0.jar:1.6.0]
> 	at org.apache.drill.exec.expr.fn.interpreter.InterpreterEvaluator$EvalVisitor.getManagedBufferIfAvailable(InterpreterEvaluator.java:158) ~[drill-java-exec-1.6.0.jar:1.6.0]
> {noformat}
> _Cause:_
> Interpreter always asks for a new buffer to hold varchar/varbinary or decimal constant values. That's why the memory size required would be proportion to # of constant expressions multiplied by # of input rows (partition). This is different from evaluation from run-time generated where constant expression will be evaluated once and use only one buffer per value.
> _Fix:_
> To use one buffer for each unique constant value in query.



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