[jira] [Created] (PARQUET-182) FilteredRecordReader skips rows it shouldn't for schema with optional columns

["Steven Mellinger (JIRA)" <ji...@apache.org>]

Steven Mellinger created PARQUET-182:
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             Summary: FilteredRecordReader skips rows it shouldn't for schema with optional columns
                 Key: PARQUET-182
                 URL: https://issues.apache.org/jira/browse/PARQUET-182
             Project: Parquet
          Issue Type: Bug
          Components: parquet-mr
    Affects Versions: 1.6.0rc2, 1.5.0
         Environment: Linux, Java7
            Reporter: Steven Mellinger
            Priority: Blocker


When using UnboundRecordFilter with nested AND/OR filters over OPTIONAL columns, there seems to be a case with a mismatch between the current record's column value and the value read during filtering.

The structure of my filter predicate that results in incorrect filtering is: (x && (y || z))

When I step through it with a debugger I can see that the value being read from the ColumnReader inside my Predicate is different than the value for that row.

Looking deeper there seems to be a buffer with dictionary keys in RunLenghBitPackingHybridDecoder (I am using RLE). There are only two different keys in this array, [0,1], whereas my optional column has three different values, [null,0,1]. If I had a column with values 5,10,10,null,10, and keys 0 -> 5 and 1 -> 10, the buffer would hold 0,1,1,1,0, and in the case that it reads the last row, would return 0 -> 5.

So it seems that nothing is keeping track of where nulls appear.

Hope someone can take a look, as it is a blocker for my project.



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