On Sun, Jun 1, 2025 at 2:23 PM Peter Geoghegan <p...@bowt.ie> wrote: > > I have to imagine that you moved rel_pages initialization back so that > it took place next to the initialization of other, similar BlockNumber > fields from LVRelState. IIRC I wrote a comment about this issue at > least in part because I understood the temptation to do that.
That sounds right. > > I'll push the fix tomorrow. > > Cool. Attached what I plan to push shortly. - Melanie
From 731dc1ef1285e167d877992eab64ebd644599926 Mon Sep 17 00:00:00 2001 From: Melanie Plageman <melanieplage...@gmail.com> Date: Mon, 2 Jun 2025 10:08:30 -0400 Subject: [PATCH v1] Correct heap vacuum boundary state setup ordering 052026c9b9 mistakenly reordered setup steps in heap_vacuum_rel(), incorrectly moving RelationGetNumberOfBlocks() before vacuum_get_cutoffs(). OldestXmin must be determined before RelationGetNumberOfBlocks() calculates the number of blocks in the relation that will be vacuumed. Otherwise tuples older than OldestXmin may be inserted into the end of the relation into blocks that are not vacuumed. If additional tuples newer than those inserted into unscanned blocks but older than OldestXmin are inserted into free space earlier in the relation, the result could be advancing pg_class.relfrozenxid to a newer value than an unfrozen XID in one of the unscanned heap pages. Assigning an incorrect relfrozenxid can lead to data loss, so it is imperative that it correctly reflect the oldest unfrozen xid. Reported-by: Peter Geoghegan <p...@bowt.ie> Author: Melanie Plageman <melanieplage...@gmail.com> Discussion: https://postgr.es/m/CAH2-WzntqvVEdbbpqG5JqSZGuLWmy4PBfUO-OswfivKchr2gvw%40mail.gmail.com --- src/backend/access/heap/vacuumlazy.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index 708674d8fcf..09416450af9 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -757,7 +757,6 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, vacrel->vm_new_visible_pages = 0; vacrel->vm_new_visible_frozen_pages = 0; vacrel->vm_new_frozen_pages = 0; - vacrel->rel_pages = orig_rel_pages = RelationGetNumberOfBlocks(rel); /* * Get cutoffs that determine which deleted tuples are considered DEAD, @@ -776,7 +775,9 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, * to increase the number of dead tuples it can prune away.) */ vacrel->aggressive = vacuum_get_cutoffs(rel, params, &vacrel->cutoffs); + vacrel->rel_pages = orig_rel_pages = RelationGetNumberOfBlocks(rel); vacrel->vistest = GlobalVisTestFor(rel); + /* Initialize state used to track oldest extant XID/MXID */ vacrel->NewRelfrozenXid = vacrel->cutoffs.OldestXmin; vacrel->NewRelminMxid = vacrel->cutoffs.OldestMxact; -- 2.34.1
