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  1. Apache Drill
  2. DRILL-4823

Fix OOM while trying to prune partitions with reasonable data size

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      Description

      Example query:

      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;
      

      Error:
      OOM while trying to prune partitions:

      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]
      

      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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              • Assignee:
                arina Arina Ielchiieva
                Reporter:
                arina Arina Ielchiieva
                Reviewer:
                Rahul Kumar Challapalli
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                • Created:
                  Updated:
                  Resolved: