diff options
| author | Heikki Linnakangas | 2025-12-05 09:32:38 +0000 |
|---|---|---|
| committer | Heikki Linnakangas | 2025-12-05 09:35:44 +0000 |
| commit | cad40cec24f338a4ac8004b58301c0809df48c03 (patch) | |
| tree | 935e48df1bcc22f48f6bdfa7787e1880aea43ba6 | |
| parent | 9d4f6d17f579ff7ead7927aba9a7742b9031d2d7 (diff) | |
Fix setting next multixid's offset at offset wraparound
In commit 789d65364c, we started updating the next multixid's offset
too when recording a multixid, so that it can always be used to
calculate the number of members. I got it wrong at offset wraparound:
we need to skip over offset 0. Fix that.
Discussion: https://www.postgresql.org/message-id/d9996478-389a-4340-8735-bfad456b313c@iki.fi
Backpatch-through: 14
| -rw-r--r-- | src/backend/access/transam/multixact.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index eb807df5ba8..60692253747 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -916,6 +916,7 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset, int64 next_pageno; int next_entryno; MultiXactOffset *next_offptr; + MultiXactOffset next_offset; LWLock *lock; LWLock *prevlock = NULL; @@ -1015,11 +1016,15 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset, next_offptr += next_entryno; } - if (*next_offptr != offset + nmembers) + /* Like in GetNewMultiXactId(), skip over offset 0 */ + next_offset = offset + nmembers; + if (next_offset == 0) + next_offset = 1; + if (*next_offptr != next_offset) { /* should already be set to the correct value, or not at all */ Assert(*next_offptr == 0); - *next_offptr = offset + nmembers; + *next_offptr = next_offset; MultiXactOffsetCtl->shared->page_dirty[slotno] = true; } |