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

• Type: Bug
• Status: Open
• Priority: Blocker
• Resolution: Unresolved
• Affects Version/s: 1.5.0, 1.6.0, 1.7.0
• Component/s: parquet-mr

Environment

Linux, Java7/Java8

• Assignee: Unassigned
• Reporter: Steven Mellinger
• Created: 06/Feb/15 03:50
• Updated: 23/Jun/24 03:27

Description

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.

Issue Links

• relates to: PARQUET-98 filter2 API performance regression