Обсуждение: [COMMITTERS] pgsql: Preserve required !catalog tuples while computing initialdecodi
[COMMITTERS] pgsql: Preserve required !catalog tuples while computing initialdecodi
От
Andres Freund
Дата:
Preserve required !catalog tuples while computing initial decoding snapshot. The logical decoding machinery already preserved all the required catalog tuples, which is sufficient in the course of normal logical decoding, but did not guarantee that non-catalog tuples were preserved during computation of the initial snapshot when creating a slot over the replication protocol. This could cause a corrupted initial snapshot being exported. The time window for issues is usually not terribly large, but on a busy server it's perfectly possible to it hit it. Ongoing decoding is not affected by this bug. To avoid increased overhead for the SQL API, only retain additional tuples when a logical slot is being created over the replication protocol. To do so this commit changes the signature of CreateInitDecodingContext(), but it seems unlikely that it's being used in an extension, so that's probably ok. In a drive-by fix, fix handling of ReplicationSlotsComputeRequiredXmin's already_locked argument, which should only apply to ProcArrayLock, not ReplicationSlotControlLock. Reported-By: Erik Rijkers Analyzed-By: Petr Jelinek Author: Petr Jelinek, heavily editorialized by Andres Freund Reviewed-By: Andres Freund Discussion: https://postgr.es/m/9a897b86-46e1-9915-ee4c-da02e4ff6a95@2ndquadrant.com Backport: 9.4, where logical decoding was introduced. Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/2bef06d51646058c6bb480fcdbffb1f0cc914fed Modified Files -------------- src/backend/replication/logical/logical.c | 25 +++++++++++++++++-------- src/backend/replication/logical/snapbuild.c | 12 ++++++++++++ src/backend/replication/slot.c | 25 +++++++++++++++++++++---- src/backend/replication/slotfuncs.c | 4 ++-- src/backend/replication/walsender.c | 1 + src/backend/storage/ipc/procarray.c | 14 +++++++++++--- src/include/replication/logical.h | 1 + src/include/storage/procarray.h | 2 +- 8 files changed, 66 insertions(+), 18 deletions(-)