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| author | Michael Paquier <michael@paquier.xyz> | 2020-01-30 11:14:02 +0900 |
|---|---|---|
| committer | Michael Paquier <michael@paquier.xyz> | 2020-01-30 11:14:02 +0900 |
| commit | b0afdcad21fde1470e6502a376bfaf0e10d384fa (patch) | |
| tree | edbb04057dd2561df41768cf6837ffbe84cf0977 /src/backend/replication | |
| parent | 26a81bb8152bd9f29bc24c1edfc00e2cbcd68548 (diff) | |
| download | postgresql-b0afdcad21fde1470e6502a376bfaf0e10d384fa.tar.gz postgresql-b0afdcad21fde1470e6502a376bfaf0e10d384fa.zip | |
Fix slot data persistency when advancing physical replication slots
Advancing a physical replication slot with pg_replication_slot_advance()
did not mark the slot as dirty if any advancing was done, preventing the
follow-up checkpoint to flush the slot data to disk. This caused the
advancing to be lost even on clean restarts. This does not happen for
logical slots as any advancing marked the slot as dirty. Per
discussion, the original feature has been implemented so as in the event
of a crash the slot may move backwards to a past LSN. This property is
kept and more documentation is added about that.
This commit adds some new TAP tests to check the persistency of physical
and logical slots after advancing across clean restarts.
Author: Alexey Kondratov, Michael Paquier
Reviewed-by: Andres Freund, Kyotaro Horiguchi, Craig Ringer
Discussion: https://postgr.es/m/059cc53a-8b14-653a-a24d-5f867503b0ee@postgrespro.ru
Backpatch-through: 11
Diffstat (limited to 'src/backend/replication')
| -rw-r--r-- | src/backend/replication/slotfuncs.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 7c896946118..e4c4401b686 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -370,6 +370,14 @@ pg_physical_replication_slot_advance(XLogRecPtr moveto) MyReplicationSlot->data.restart_lsn = moveto; SpinLockRelease(&MyReplicationSlot->mutex); retlsn = moveto; + + /* + * Dirty the slot so as it is written out at the next checkpoint. + * Note that the LSN position advanced may still be lost in the + * event of a crash, but this makes the data consistent after a + * clean shutdown. + */ + ReplicationSlotMarkDirty(); } return retlsn; @@ -467,9 +475,9 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * keep track of their progress, so we should make more of an * effort to save it for them. * - * Dirty the slot so it's written out at the next checkpoint. - * We'll still lose its position on crash, as documented, but it's - * better than always losing the position even on clean restart. + * Dirty the slot so it is written out at the next checkpoint. + * The LSN position advanced to may still be lost on a crash + * but this makes the data consistent after a clean shutdown. */ ReplicationSlotMarkDirty(); } @@ -566,15 +574,6 @@ pg_replication_slot_advance(PG_FUNCTION_ARGS) values[0] = NameGetDatum(&MyReplicationSlot->data.name); nulls[0] = false; - /* Update the on disk state when lsn was updated. */ - if (XLogRecPtrIsInvalid(endlsn)) - { - ReplicationSlotMarkDirty(); - ReplicationSlotsComputeRequiredXmin(false); - ReplicationSlotsComputeRequiredLSN(); - ReplicationSlotSave(); - } - ReplicationSlotRelease(); /* Return the reached position. */ |