Horton

RE: Synchronizing slots from primary to standby

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

View thread View on postgr.es
From: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, shveta malik <shveta.malik@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Bruce Momjian <bruce@momjian.us>, Ashutosh Sharma <ashu.coek88@gmail.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2024-02-13T01:15:48Z
Lists: pgsql-hackers

Attachments

On Monday, February 12, 2024 5:40 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> 
> On Sun, Feb 11, 2024 at 6:53 PM Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>
> wrote:
> >
> > Agreed. Here is the V84 patch which addressed this.
> >
> 
> Few comments:
> =============
> 1. Isn't the new function (pg_sync_replication_slots()) allowed to sync the slots
> from physical standby to another cascading standby?
> Won't it be better to simply disallow syncing slots on cascading standby to keep
> it consistent with slotsync worker behavior?
> 
> 2.
> Previously, I commented to keep the declaration and definition of functions in
> the same order but I see that it still doesn't match in the below case:
> 
> @@ -44,6 +46,7 @@ extern void WalSndWakeup(bool physical, bool logical);
> extern void WalSndInitStopping(void); extern void WalSndWaitStopping(void);
> extern void HandleWalSndInitStopping(void);
> +extern XLogRecPtr GetStandbyFlushRecPtr(TimeLineID *tli);
> extern void WalSndRqstFileReload(void);
> 
> I think we can keep the new declaration just before WalSndSignals().
> That would be more consistent.
> 
> 3.
> +      <para>
> +      True if this is a logical slot that was synced from a primary server.
> +      </para>
> +      <para>
> +       On a hot standby, the slots with the synced column marked as true can
> +       neither be used for logical decoding nor dropped by the user.
> + The value
> 
> I don't think we need a separate para here.
> 
> Apart from this, I have made several cosmetic changes in the attached.
> Please include these in the next version unless you see any problems.

Thanks for the comments, I have addressed them.

Here is the new version patch which addressed above and
most of Bertrand's comments.

TODO: trying to add one test for the case the slot is valid on
primary while the synced slots is invalidated on the standby.

Best Regards,
Houzj

Commits

  1. Doc: Add the new section "Logical Replication Failover".

  2. Fix the review comments and a bug in the slot sync code.

  3. Fix a test in failover slots regression test.

  4. Fix the intermittent buildfarm failures in 040_standby_failover_slots_sync.

  5. Split XLogCtl->LogwrtResult into separate struct members

  6. Ensure that the sync slots reach a consistent state after promotion without losing data.

  7. Introduce a new GUC 'standby_slot_names'.

  8. Fix BF failure introduced by commit b3f6b14cf4.

  9. Fixups for commit 93db6cbda0.

  10. Fix BF failure in commit 93db6cbda0.

  11. Add a new slot sync worker to synchronize logical slots.

  12. Improve ERROR/LOG messages added by commits ddd5f4f54a and 7a424ece48.

  13. Disable autovacuum on primary in 040_standby_failover_slots_sync test.

  14. Fix the incorrect format specifier used in commit 7a424ece48.

  15. Change the LOG level in 040_standby_failover_slots_sync.pl to DEBUG2.

  16. Add more LOG and DEBUG messages for slot synchronization.

  17. Another try to fix BF failure introduced in commit ddd5f4f54a.

  18. Fix BF introduced in commit ddd5f4f54a.

  19. Add a slot synchronization function.

  20. Clean-ups for 776621a5e4 and 7329240437.

  21. Enhance libpqrcv APIs to support slot synchronization.

  22. Add a failover option to subscriptions.

  23. Allow setting failover property in the replication command.

  24. Allow to enable failover property for replication slots via SQL API.

  25. Add macros for looping through a List without a ListCell.

  26. Track conflict_reason in pg_replication_slots.

  27. Allow upgrades to preserve the full subscription's state.

  28. Add support for incremental backup.

  29. Simplify some logic in CreateReplicationSlot()

  30. Fix uninitialized access to InitialRunningXacts during decoding after ERROR.

  31. Flexible options for CREATE_REPLICATION_SLOT.

  32. Empty search_path in logical replication apply worker and walsender.

  33. Fix oldest xmin and LSN computation across repslots after advancing

  34. Require C99 (and thus MSCV 2013 upwards).