Maryann Xue created PHOENIX-1456:
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Summary: Incorrect query results caused by reusing buffers in
SpoolingResultIterator
Key: PHOENIX-1456
URL: https://issues.apache.org/jira/browse/PHOENIX-1456
Project: Phoenix
Issue Type: Bug
Affects Versions: 3.0.0, 4.0.0, 5.0.0
Reporter: Maryann Xue
The SpoolingResultIterator#OnDiskResultIterator switches between two
pre-allocated buffers as reading buffers for the tuple result, based on the
assumption that the outer ResultIterator consumes the returned tuple in a
streaming fashion and will never look back/forward outside 2-tuple span.
However, some usages fail this assumption:
1. OrderedResultIterator: It adds all tuples into its MappedByteBufferQueue on
initialization, which is maintained by a priority queue before threshold is
reached and spooling to files.
This is not revealed in most test cases because, most importantly,
OrderedResultIterator is not commonly used on clientside (only
ClientProcessingPlan does)
2. Child/parent hash-join optimization, which uses a list of PK values to
create an InListExpression.
It might be easy to walk around the second usage here though, but may need more
consideration on the first one.
I am thinking to take away SpoolingResultIterator at all if there is an outer
ResultIterator being OrderedResultIterator.
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