Sergey Soldatov created PHOENIX-4018:
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Summary: HashJoin may produce nulls for LHS table columns
Key: PHOENIX-4018
URL: https://issues.apache.org/jira/browse/PHOENIX-4018
Project: Phoenix
Issue Type: Bug
Affects Versions: 4.11.0
Reporter: Sergey Soldatov
Assignee: Sergey Soldatov
Priority: Critical
Here is the problem: in HashJoinRegionScanner methods (nextRow for example) we
are using the same scanner context that was created in RSRpcServices. It has
limits (i.e. 2Mb size). Let's say that we have 3Mb region and the only key that
match the join condition is located at the end of the region. In
HashJoinRegionScanner#nextRow when we iterate through the region rows once we
reached the limit of 2Mb, every region scanner nextRow will return a single
cell and the scanner context will have SIZE_LIMIT_REACHED_MID_ROW state. But we
don't have any logic that check that, so this single cell is considered as a
complete row with all nulls except one column.
How to fix it:
1. for region scanner we may provide NoLimitScannerContext, so we will never
get a partial result.
2. We need to update the scanner context that we got from RSRpcServices with
the real data, basing on the size of results we are going to return.
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