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Persist slot invalidation correctly

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We failed to save slot to disk after invalidating it, so the state was
lost in case of server restart or crash.  Fix by marking it dirty and
flushing.

Also, if the slot is known invalidated we don't need to reason about the
LSN at all -- it's known invalidated.  Only test the LSN if the slot is
known not invalidated.

Author: Fujii Masao <masao.fujii@oss.nttdata.com>
Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/17a69cfe-f1c1-a416-ee25-ae15427c69eb@oss.nttdata.com
This commit is contained in:
Alvaro Herrera 2020-06-26 20:41:29 -04:00
parent eca08f58d0
commit 4ae08cd5fd
No known key found for this signature in database
GPG Key ID: 1C20ACB9D5C564AE
2 changed files with 13 additions and 12 deletions
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9
src/backend/replication/slot.c
View File

@ -1157,6 +1157,7 @@ restart:
if (XLogRecPtrIsInvalid(restart_lsn) || restart_lsn >= oldestLSN) if (XLogRecPtrIsInvalid(restart_lsn) || restart_lsn >= oldestLSN)
continue; continue;
LWLockRelease(ReplicationSlotControlLock); LWLockRelease(ReplicationSlotControlLock);
CHECK_FOR_INTERRUPTS();
/* Get ready to sleep on the slot in case it is active */ /* Get ready to sleep on the slot in case it is active */
ConditionVariablePrepareToSleep(&s->active_cv); ConditionVariablePrepareToSleep(&s->active_cv);
@ -1214,10 +1215,7 @@ restart:
* already been dropped. * already been dropped.
*/ */
if (wspid == -1) if (wspid == -1)
{
CHECK_FOR_INTERRUPTS();
goto restart; goto restart;
}
ereport(LOG, ereport(LOG,
(errmsg("invalidating slot \"%s\" because its restart_lsn %X/%X exceeds max_slot_wal_keep_size", (errmsg("invalidating slot \"%s\" because its restart_lsn %X/%X exceeds max_slot_wal_keep_size",
@ -1229,10 +1227,13 @@ restart:
s->data.invalidated_at = s->data.restart_lsn; s->data.invalidated_at = s->data.restart_lsn;
s->data.restart_lsn = InvalidXLogRecPtr; s->data.restart_lsn = InvalidXLogRecPtr;
SpinLockRelease(&s->mutex); SpinLockRelease(&s->mutex);
/* Make sure the invalidated state persists across server restart */
ReplicationSlotMarkDirty();
ReplicationSlotSave();
ReplicationSlotRelease(); ReplicationSlotRelease();
/* if we did anything, start from scratch */ /* if we did anything, start from scratch */
CHECK_FOR_INTERRUPTS();
goto restart; goto restart;
} }
LWLockRelease(ReplicationSlotControlLock); LWLockRelease(ReplicationSlotControlLock);

16
src/backend/replication/slotfuncs.c
View File

@ -283,7 +283,6 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
bool nulls[PG_GET_REPLICATION_SLOTS_COLS]; bool nulls[PG_GET_REPLICATION_SLOTS_COLS];
WALAvailability walstate; WALAvailability walstate;
XLogSegNo last_removed_seg; XLogSegNo last_removed_seg;
XLogRecPtr targetLSN;
int i; int i;
if (!slot->in_use) if (!slot->in_use)
@ -344,14 +343,15 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
nulls[i++] = true; nulls[i++] = true;
/* /*
* Report availability from invalidated_at when the slot has been * If invalidated_at is valid and restart_lsn is invalid, we know for
* invalidated; otherwise slots would appear as invalid without any * certain that the slot has been invalidated. Otherwise, test
* more clues as to what happened. * availability from restart_lsn.
*/ */
targetLSN = XLogRecPtrIsInvalid(slot_contents.data.restart_lsn) ? if (XLogRecPtrIsInvalid(slot_contents.data.restart_lsn) &&
slot_contents.data.invalidated_at : !XLogRecPtrIsInvalid(slot_contents.data.invalidated_at))
slot_contents.data.restart_lsn; walstate = WALAVAIL_REMOVED;
walstate = GetWALAvailability(targetLSN); else
walstate = GetWALAvailability(slot_contents.data.restart_lsn);
switch (walstate) switch (walstate)
{ {