Horton

Re: Synchronizing slots from primary to standby

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Amit Kapila <amit.kapila16@gmail.com>
Cc: shveta malik <shveta.malik@gmail.com>, Peter Smith <smithpb2250@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>, Ajin Cherian <itsajin@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2023-11-27T12:46:05Z
Lists: pgsql-hackers 
Hi,

On 11/27/23 1:23 PM, Zhijie Hou (Fujitsu) wrote:
> On Monday, November 27, 2023 8:05 PM Drouvot, Bertrand <bertranddrouvot.pg@gmail.com> wrote:
>> Did not look in details but it looks like there is more to do here as
>> this is failing (with v39_2):
>>
>> "
>> postgres@primary: psql replication=database
>> psql (17devel)
>> Type "help" for help.
>>
>> postgres=# CREATE_REPLICATION_SLOT test_logical20 LOGICAL pgoutput
>> FAILOVER;
>> ERROR:  syntax error
> 
> I think the command you executed is of old syntax style, which was kept for
> compatibility with older releases. And I think we can avoid supporting new
> option for the old syntax as described in the original thread[1] of commit
> 0266e98. So, the "syntax error" is as expected IIUC.
> 
> The new style command is like:
> CREATE_REPLICATION_SLOT test_logical20 LOGICAL pgoutput (FAILOVER);
> 
> [1] https://www.postgresql.org/message-id/CA%2BTgmobAczXDRO_Gr2euo_TxgzaH1JxbNxvFx%3DHYvBinefNH8Q%40mail.gmail.com
> 

Oh, I see, thanks for pointing out.

Well, not related to that thread but it seems weird to me that the backward
compatibility is done at the "option" level then.

I think it would make more sense to support all the options if the old
syntax is still supported.

For example, having

postgres=# CREATE_REPLICATION_SLOT test_logical2 LOGICAL pgoutput TWO_PHASE;

working fine but

CREATE_REPLICATION_SLOT test_logical3 LOGICAL pgoutput FAILOVER;

failing looks weird to me.

But that's probably out of this thread's context anyway.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

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).