Simon Riggs wrote:
The idea outlined before didn't deal with all call points for
RecordIsCleanupRecord(), so doesn't actually work.
Hmm, grep finds two call points for that:
! case RECOVERY_TARGET_PAUSE_CLEANUP:
! /*
! * Advance until we see a cleanup
record, then pause.
! */
! if (RecordIsCleanupRecord(record))
! pauseHere = true;
! break;
!
and
+ /*
+ * Wait, kill or otherwise resolve any
conflicts between
+ * incoming cleanup records and user
queries. This is the
+ * main barrier that allows MVCC to work correctly when
+ * running standby servers. Only need to do this if there
+ * is a possibility that users may be
active.
+ */
+ if (reachedSafeStartPoint &&
RecordIsCleanupRecord(record))
+
ResolveRedoVisibilityConflicts(EndRecPtr, record);
The second we can easily handle by getting rid of
ResolveRedoVisibilityConflicts functions and making the redo-functions
call XactResolveRecoveryConflicts when necessary.
Is the first really useful? I would understand "advance until next
cleanup record *that would block/kill queries*", but why would you want
to advance until the next cleanup record? Anyway, if it is useful, you
could do the pausing in XactResolveRecoveryConflicts, too.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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