Обсуждение: lost replication slots after pg_upgrade
Hi
One customer reports issue related to pg_upgrade.
I found a thread https://www.postgresql-archive.org/Upgrade-and-re-synchronization-with-logical-replication-pglogical-and-PG-10-td6001990.html
But I didn't find documentation of this limitation?
Regards
Pavel
On Tue, Oct 13, 2020 at 06:20:41PM +0200, Pavel Stehule wrote: > Hi > > One customer reports issue related to pg_upgrade. > > I found a thread https://www.postgresql-archive.org/ > Upgrade-and-re-synchronization-with-logical-replication-pglogical-and-PG-10-td6001990.html > > But I didn't find documentation of this limitation? So, what is the question? Peter Eisentraut is right that WAL is not preserved, so replication slots are not preserved. We do have pg_upgrade instructions for upgrading binary replication, but I assume people recreate the slots. -- Bruce Momjian <bruce@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
út 13. 10. 2020 v 18:33 odesílatel Bruce Momjian <bruce@momjian.us> napsal:
On Tue, Oct 13, 2020 at 06:20:41PM +0200, Pavel Stehule wrote:
> Hi
>
> One customer reports issue related to pg_upgrade.
>
> I found a thread https://www.postgresql-archive.org/
> Upgrade-and-re-synchronization-with-logical-replication-pglogical-and-PG-10-td6001990.html
>
> But I didn't find documentation of this limitation?
So, what is the question? Peter Eisentraut is right that WAL is not
preserved, so replication slots are not preserved. We do have
pg_upgrade instructions for upgrading binary replication, but I assume
people recreate the slots.
I cannot find related documentation.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
On Tue, Oct 13, 2020 at 06:37:14PM +0200, Pavel Stehule wrote: > > > út 13. 10. 2020 v 18:33 odesílatel Bruce Momjian <bruce@momjian.us> napsal: > > On Tue, Oct 13, 2020 at 06:20:41PM +0200, Pavel Stehule wrote: > > Hi > > > > One customer reports issue related to pg_upgrade. > > > > I found a thread https://www.postgresql-archive.org/ > > > Upgrade-and-re-synchronization-with-logical-replication-pglogical-and-PG-10-td6001990.html > > > > But I didn't find documentation of this limitation? > > So, what is the question? Peter Eisentraut is right that WAL is not > preserved, so replication slots are not preserved. We do have > pg_upgrade instructions for upgrading binary replication, but I assume > people recreate the slots. > > > I cannot find related documentation. You mean related documentation of how to manage changing replication slots? -- Bruce Momjian <bruce@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
út 13. 10. 2020 v 18:57 odesílatel Bruce Momjian <bruce@momjian.us> napsal:
On Tue, Oct 13, 2020 at 06:37:14PM +0200, Pavel Stehule wrote:
>
>
> út 13. 10. 2020 v 18:33 odesílatel Bruce Momjian <bruce@momjian.us> napsal:
>
> On Tue, Oct 13, 2020 at 06:20:41PM +0200, Pavel Stehule wrote:
> > Hi
> >
> > One customer reports issue related to pg_upgrade.
> >
> > I found a thread https://www.postgresql-archive.org/
> >
> Upgrade-and-re-synchronization-with-logical-replication-pglogical-and-PG-10-td6001990.html
> >
> > But I didn't find documentation of this limitation?
>
> So, what is the question? Peter Eisentraut is right that WAL is not
> preserved, so replication slots are not preserved. We do have
> pg_upgrade instructions for upgrading binary replication, but I assume
> people recreate the slots.
>
>
> I cannot find related documentation.
You mean related documentation of how to manage changing replication
slots?
no, I just missi note, so after upgrade by pg_upgrade I have to recreate replication slots. Some like
after pg_upgrade you should to do:
a) run analyze .... (it is a known case)
b) recreate replication slots - these slots are not removed in the upgrade process.
Regards
Pavel
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
On 2020-10-13 19:23, Pavel Stehule wrote: > no, I just missi note, so after upgrade by pg_upgrade I have to recreate > replication slots. Some like > > after pg_upgrade you should to do: > > a) run analyze .... (it is a known case) > b) recreate replication slots - these slots are not removed in the > upgrade process. An argument could be made that pg_upgrade should copy over logical replication slots. The normal scenario would be that you pause your logical subscriptions, run pg_upgrade on the publisher, then un-pause the subscriptions. The subscribers then ought to be able to reconnect and continue consuming logical changes. Since the content of the publisher database is logically the same before and after the upgrade, this should appear transparent to the subscribers. They'll just see that the publisher was offline for a while. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
On Tue, Oct 13, 2020 at 11:34:27PM +0200, Peter Eisentraut wrote: > On 2020-10-13 19:23, Pavel Stehule wrote: > > no, I just missi note, so after upgrade by pg_upgrade I have to recreate > > replication slots. Some like > > > > after pg_upgrade you should to do: > > > > a) run analyze .... (it is a known case) > > b) recreate replication slots - these slots are not removed in the > > upgrade process. > > An argument could be made that pg_upgrade should copy over logical > replication slots. The normal scenario would be that you pause your logical > subscriptions, run pg_upgrade on the publisher, then un-pause the > subscriptions. The subscribers then ought to be able to reconnect and > continue consuming logical changes. Since the content of the publisher > database is logically the same before and after the upgrade, this should > appear transparent to the subscribers. They'll just see that the publisher > was offline for a while. I guess that is possible since pg_upgrade resets the WAL location, though not the WAL contents. -- Bruce Momjian <bruce@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee