Hi,
On 10/20/23 5:27 AM, shveta malik wrote:
On Wed, Oct 18, 2023 at 4:24 PM Amit Kapila <amit.kapil...@gmail.com> wrote:
PFA v25 patch set. The changes are:
1) 'enable_failover' is changed to 'failover'
2) Alter subscription changes to support 'failover'
3) Fixes a bug in patch001 wherein any change in standby_slot_names
was not considered in the flow where logical walsenders wait for
standby's confirmation. Now during the wait, if standby_slot_names is
changed, wait is restarted using new standby_slot_names.
4) Addresses comments by Bertrand and Amit in [1],[2],[3]
The changes are mostly in patch001 and a very few in patch002.
Thank You Ajin for working on alter-subscription changes and adding
more TAP-tests for 'failover'
Thanks for updating the patch!
Looking at 0001 and doing some experiment:
Creating a logical slot with failover = true and then launching
pg_logical_slot_get_changes() or pg_recvlogical() on it results
to setting failover back to false.
It occurs while creating the decoding context here:
@@ -602,6 +602,9 @@ CreateDecodingContext(XLogRecPtr start_lsn,
SnapBuildSetTwoPhaseAt(ctx->snapshot_builder, start_lsn);
}
+ /* set failover in the slot, as requested */
+ slot->data.failover = ctx->failover;
+
I think we can get rid of this change in CreateDecodingContext().
Looking at 0002:
/* Enter main loop */
for (;;)
{
int rc;
long wait_time = DEFAULT_NAPTIME_PER_CYCLE;
CHECK_FOR_INTERRUPTS();
/*
* If it is Hot standby, then try to launch slot-sync workers else
* launch apply workers.
*/
if (RecoveryInProgress())
{
/* Launch only if we have succesfully made the connection */
if (wrconn)
LaunchSlotSyncWorkers(&wait_time, wrconn);
}
We are waiting for DEFAULT_NAPTIME_PER_CYCLE (3 minutes) before checking if
there
is new synced slot(s) to be created on the standby. Do we want to keep this
behavior
for V1?
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
