RelationTruncate() must set DELAY_CHKPT_START. Previously, it set only DELAY_CHKPT_COMPLETE. That was important, because it meant that if the XLOG_SMGR_TRUNCATE record preceded a XLOG_CHECKPOINT_ONLINE record in the WAL, then the truncation would also happen on disk before the XLOG_CHECKPOINT_ONLINE record was written.
However, it didn't guarantee that the sync request for the truncation was processed before the XLOG_CHECKPOINT_ONLINE record was written. By setting DELAY_CHKPT_START, we guarantee that if an XLOG_SMGR_TRUNCATE record is written to WAL before the redo pointer of a concurrent checkpoint, the sync request queued by that operation must be processed by that checkpoint, rather than being left for the following one. This is a refinement of commit 412ad7a5563. Back-patch to all supported releases, like that commit. Author: Robert Haas <robertmh...@gmail.com> Reported-by: Thomas Munro <thomas.mu...@gmail.com> Discussion: https://postgr.es/m/CA%2BhUKG%2B-2rjGZC2kwqr2NMLBcEBp4uf59QT1advbWYF_uc%2B0Aw%40mail.gmail.com Branch ------ REL_13_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/1168acbca475d48f745b345f69389df11f2396aa Modified Files -------------- src/backend/catalog/storage.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-)
