From 67bab53d64428e4d43386be0e077cd662bc9cad3 Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Thu, 24 Oct 2024 09:16:38 -0700 Subject: [PATCH] Fix parallel worker tracking of new catalog relfilenumbers. Reunite RestorePendingSyncs() with RestoreRelationMap(). If RelationInitPhysicalAddr() ran after RestoreRelationMap() but before RestorePendingSyncs(), the relcache entry could cause RelationNeedsWAL() to return true erroneously. Trouble required commands of the current transaction to include REINDEX or CLUSTER of a system catalog. The parallel leader correctly derived RelationNeedsWAL()==false from the new relfilenumber, but the worker saw RelationNeedsWAL()==true. Worker MarkBufferDirtyHint() then wrote unwanted WAL. Recovery of that unwanted WAL could lose tuples like the system could before commit c6b92041d38512a4176ed76ad06f713d2e6c01a8 introduced this tracking. RestorePendingSyncs() and RestoreRelationMap() were adjacent till commit 126ec0bc76d044d3a9eb86538b61242bf7da6db4, so no back-patch for now. Reviewed by Tom Lane. Discussion: https://postgr.es/m/20241019232815.c6.nmisch@google.com --- src/backend/access/transam/parallel.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index d4e84aabac7..4a2e352d579 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -1421,17 +1421,18 @@ ParallelWorkerMain(Datum main_arg) StartParallelWorkerTransaction(tstatespace); /* - * Restore relmapper and reindex state early, since these affect catalog - * access. Ideally we'd do this even before calling InitPostgres, but - * that has order-of-initialization problems, and also the relmapper would - * get confused during the CommitTransactionCommand call above. + * Restore state that affects catalog access. Ideally we'd do this even + * before calling InitPostgres, but that has order-of-initialization + * problems, and also the relmapper would get confused during the + * CommitTransactionCommand call above. */ + pendingsyncsspace = shm_toc_lookup(toc, PARALLEL_KEY_PENDING_SYNCS, + false); + RestorePendingSyncs(pendingsyncsspace); relmapperspace = shm_toc_lookup(toc, PARALLEL_KEY_RELMAPPER_STATE, false); RestoreRelationMap(relmapperspace); reindexspace = shm_toc_lookup(toc, PARALLEL_KEY_REINDEX_STATE, false); RestoreReindexState(reindexspace); - - /* Restore combo CID state. */ combocidspace = shm_toc_lookup(toc, PARALLEL_KEY_COMBO_CID, false); RestoreComboCIDState(combocidspace); @@ -1488,11 +1489,6 @@ ParallelWorkerMain(Datum main_arg) SetTempNamespaceState(fps->temp_namespace_id, fps->temp_toast_namespace_id); - /* Restore pending syncs. */ - pendingsyncsspace = shm_toc_lookup(toc, PARALLEL_KEY_PENDING_SYNCS, - false); - RestorePendingSyncs(pendingsyncsspace); - /* Restore uncommitted enums. */ uncommittedenumsspace = shm_toc_lookup(toc, PARALLEL_KEY_UNCOMMITTEDENUMS, false); -- 2.30.2