Hi,
On 10/9/23 12:30 PM, shveta malik wrote:
PFA v22 patch-set. It has below changes:
patch 001:
1) Now physical walsender wakes up logical walsender(s) by using a new
CV as suggested in [1]
Thanks!
I think that works fine as long as the standby is up and running and catching
up.
The problem I see with the current WalSndWaitForStandbyConfirmation()
implementation
is that if the standby is not running then:
+ for (;;)
+ {
+ ListCell *l;
+ long sleeptime = -1;
will loop until we reach the "terminating walsender process due to replication
timeout" if we
explicitly want to end with SIGINT or friends.
For example a scenario like:
- standby down
- pg_recvlogical running
then CTRL-C on pg_recvlogical would not "respond" immediately but when we reach
the replication timeout.
So it seems that we should use something like WalSndWait() instead of
ConditionVariableTimedSleep() here:
+ /*
+ * Sleep until other physical walsenders awaken us or until a
timeout
+ * occurs.
+ */
+ sleeptime = WalSndComputeSleeptime(GetCurrentTimestamp());
+
+ ConditionVariableTimedSleep(&WalSndCtl->wal_confirm_rcv_cv,
sleeptime,
+
WAIT_EVENT_WAL_SENDER_WAIT_FOR_STANDBY_CONFIRMATION);
In that case I think that WalSndWait() should take care of the new CV
WalSndCtl->wal_confirm_rcv_cv too.
The wait on the socket should allow us to stop waiting when, for example,
CTRL-C on pg_recvlogical is triggered.
Then we would need to deal with this scenario: Standby down or not catching up
and exited WalSndWait() due to the socket
to break the loop or shutdown the walsender.
Thoughts?
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
