Horton

Disallow partitionwise join when collations don't match

Amit Langote <amitlan@postgresql.org>

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Commit: 33040b1715c7a3450a6b3dc61bd7779a5f9ae709
Author: Amit Langote <amitlan@postgresql.org>
Date: 2024-11-08T08:18:55Z
Releases: 15.9 
Disallow partitionwise join when collations don't match

If the collation of any join key column doesn’t match the collation of
the corresponding partition key, partitionwise joins can yield incorrect
results. For example, rows that would match under the join key collation
might be located in different partitions due to the partitioning
collation. In such cases, a partitionwise join would yield different
results from a non-partitionwise join, so disallow it in such cases.

Reported-by: Tender Wang <tndrwang@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Junwang Zhao <zhjwpku@gmail.com>
Discussion: https://postgr.es/m/CAHewXNno_HKiQ6PqyLYfuqDtwp7KKHZiH1J7Pqyz0nr+PS2Dwg@mail.gmail.com
Backpatch-through: 12

Files

PathChange+/−
src/backend/optimizer/util/relnode.c modified +4 −0
src/test/regress/expected/collate.icu.utf8.out modified +118 −0
src/test/regress/sql/collate.icu.utf8.sql modified +22 −0

Discussion