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pgsql: Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOU 2+ messages / 1 participants [nested] [flat]
* pgsql: Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOU @ 2024-10-03 12:49 Dean Rasheed <dean.a.rasheed@gmail.com> 0 siblings, 0 replies; 2+ messages in thread From: Dean Rasheed @ 2024-10-03 12:49 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOURCE. If a MERGE command contains WHEN NOT MATCHED BY SOURCE actions, the source relation appears on the outer side of the join. Thus, any Vars referring to the source in the merge join condition, actions, and RETURNING list should be marked as nullable by the join, since they are used in the ModifyTable node above the join. Note that this only applies to the copy of join condition used in the executor to distinguish MATCHED from NOT MATCHED BY SOURCE cases. Vars in the original join condition, inside the join node itself, should not be marked. Failure to correctly mark these Vars led to a "wrong varnullingrels" error in the final stage of query planning, in some circumstances. We happened to get away without this in all previous tests, since they all involved a ModifyTable node directly on top of the join node, so that the top plan targetlist coincided with the output of the join, and the varnullingrels check was more lax. However, if another plan node, such as a one-time filter Result node, gets inserted between the ModifyTable node and the join node, then a stricter check is applied, which fails. Per bug #18634 from Alexander Lakhin. Thanks to Tom Lane and Richard Guo for review and analysis. Back-patch to v17, where WHEN NOT MATCHED BY SOURCE support was added to MERGE. Discussion: https://postgr.es/m/18634-db5299c937877f2b%40postgresql.org Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/259a0a99fe3d45dcf624788c1724d9989f3382dc Modified Files -------------- src/backend/optimizer/prep/prepjointree.c | 39 +++++++++++++++++++++++++++++++ src/test/regress/expected/merge.out | 29 +++++++++++++++++++++++ src/test/regress/sql/merge.sql | 21 +++++++++++++++++ 3 files changed, 89 insertions(+) ^ permalink raw reply [nested|flat] 2+ messages in thread
* pgsql: Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOU @ 2024-10-03 12:49 Dean Rasheed <dean.a.rasheed@gmail.com> 0 siblings, 0 replies; 2+ messages in thread From: Dean Rasheed @ 2024-10-03 12:49 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOURCE. If a MERGE command contains WHEN NOT MATCHED BY SOURCE actions, the source relation appears on the outer side of the join. Thus, any Vars referring to the source in the merge join condition, actions, and RETURNING list should be marked as nullable by the join, since they are used in the ModifyTable node above the join. Note that this only applies to the copy of join condition used in the executor to distinguish MATCHED from NOT MATCHED BY SOURCE cases. Vars in the original join condition, inside the join node itself, should not be marked. Failure to correctly mark these Vars led to a "wrong varnullingrels" error in the final stage of query planning, in some circumstances. We happened to get away without this in all previous tests, since they all involved a ModifyTable node directly on top of the join node, so that the top plan targetlist coincided with the output of the join, and the varnullingrels check was more lax. However, if another plan node, such as a one-time filter Result node, gets inserted between the ModifyTable node and the join node, then a stricter check is applied, which fails. Per bug #18634 from Alexander Lakhin. Thanks to Tom Lane and Richard Guo for review and analysis. Back-patch to v17, where WHEN NOT MATCHED BY SOURCE support was added to MERGE. Discussion: https://postgr.es/m/18634-db5299c937877f2b%40postgresql.org Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/34ae54af92e006e601f808e58765cc979ca9135f Modified Files -------------- src/backend/optimizer/prep/prepjointree.c | 39 +++++++++++++++++++++++++++++++ src/test/regress/expected/merge.out | 29 +++++++++++++++++++++++ src/test/regress/sql/merge.sql | 21 +++++++++++++++++ 3 files changed, 89 insertions(+) ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2024-10-03 12:49 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-10-03 12:49 pgsql: Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOU Dean Rasheed <dean.a.rasheed@gmail.com> 2024-10-03 12:49 pgsql: Fix wrong varnullingrels error for MERGE WHEN NOT MATCHED BY SOU Dean Rasheed <dean.a.rasheed@gmail.com>
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