Horton

Fix YA incremental sort bug.

Tom Lane <tgl@sss.pgh.pa.us>

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Commit: 82e0e29308dedbc6000e73329beb112ae7e1ad39
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: 2021-02-05T00:12:14Z
Releases: 14.0 
Fix YA incremental sort bug.

switchToPresortedPrefixMode() did the wrong thing if it detected
a batch boundary just at the last tuple of a fullsort group.

The initially-reported symptom was a "retrieved too many tuples in a
bounded sort" error, but the test case added here just silently gives
the wrong answer without this patch.

I (tgl) am not really happy about committing this patch without review
from the incremental-sort authors, but they seem AWOL and we are hard
against a release deadline.  This does demonstrably make some cases
better, anyway.

Per bug #16846 from Yoran Heling.  Back-patch to v13 where incremental
sort was introduced.

Neil Chen

Discussion: https://postgr.es/m/16846-ae49f51ac379a4cb@postgresql.org

Files

PathChange+/−
src/backend/executor/nodeIncrementalSort.c modified +7 −0
src/test/regress/expected/incremental_sort.out modified +11 −0
src/test/regress/sql/incremental_sort.sql modified +3 −0

Discussion