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author | Thomas Munro <tmunro@postgresql.org> | 2023-07-03 16:16:27 +1200 |
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committer | Thomas Munro <tmunro@postgresql.org> | 2023-07-04 09:20:55 +1200 |
commit | 8f705d7b9d01a0b9ab350bca9fc17ded333faca9 (patch) | |
tree | 31f8613905bc238290262bee11ce14412ad04f70 /src/backend/access/heap/heapam_handler.c | |
parent | 753f20c179f7be94a335e9dc67a5d58c6036d119 (diff) | |
download | postgresql-8f705d7b9d01a0b9ab350bca9fc17ded333faca9.tar.gz postgresql-8f705d7b9d01a0b9ab350bca9fc17ded333faca9.zip |
Fix race in SSI interaction with empty btrees.
When predicate-locking btrees, we have a special case for completely
empty btrees, since there is no page to lock. This was racy, because,
without buffer lock held, a matching key could be inserted between the
_bt_search() and the PredicateLockRelation() calls.
Fix, by rechecking _bt_search() after taking the relation-level SIREAD
lock, if using SERIALIZABLE isolation and an empty btree is discovered.
Back-patch to all supported releases. Fixes one aspect of bug #17949.
Reported-by: Artem Anisimov <artem.anisimov.255@gmail.com>
Reviewed-by: Dmitry Dolgov <9erthalion6@gmail.com>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/17949-a0f17035294a55e2%40postgresql.org
Diffstat (limited to 'src/backend/access/heap/heapam_handler.c')
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