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Assert in init_toast_snapshot() that some snapshot registered or active.

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Commit <FIXME> fixed the bug that RemoveTempRelationsCallback() did not
push/register a snapshot. That only went unnoticed because often a valid
catalog snapshot exists and is returned by GetOldestSnapshot(). But due to
invalidation processing that is not reliable.

Thus assert in init_toast_snapshot() that there is a registered or active
snapshot, using the new HaveRegisteredOrActiveSnapshot().

Author: Andres Freund
Discussion: https://postgr.es/m/20220219180002.6tubjq7iw7m52bgd@alap3.anarazel.de
This commit is contained in:
Andres Freund
2022-02-19 12:42:37 -08:00
parent 7c38ef2a5d
commit 2776922201
3 changed files with 36 additions and 0 deletions
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26
src/backend/utils/time/snapmgr.c
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@@ -1625,6 +1625,32 @@ ThereAreNoPriorRegisteredSnapshots(void)
return false;
}
/*
* HaveRegisteredOrActiveSnapshots
* Is there any registered or active snapshot?
*
* NB: Unless pushed or active, the cached catalog snapshot will not cause
* this function to return true. That allows this function to be used in
* checks enforcing a longer-lived snapshot.
*/
bool
HaveRegisteredOrActiveSnapshot(void)
{
if (ActiveSnapshot != NULL)
return true;
/*
* The catalog snapshot is in RegisteredSnapshots when valid, but can be
* removed at any time due to invalidation processing. If explicitly
* registered more than one snapshot has to be in RegisteredSnapshots.
*/
if (pairingheap_is_empty(&RegisteredSnapshots) ||
!pairingheap_is_singular(&RegisteredSnapshots))
return false;
return CatalogSnapshot == NULL;
}
/*
* Return a timestamp that is exactly on a minute boundary.