Horton

RE: Synchronizing slots from primary to standby

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

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From: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: shveta malik <shveta.malik@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Masahiko Sawada <sawada.mshk@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: 2024-02-10T03:37:25Z
Lists: pgsql-hackers

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On Friday, February 9, 2024 6:45 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> 
> On Fri, Feb 9, 2024 at 10:00 AM Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>
> wrote:
> >
> 
> Few comments on 0001
> ===================
> 1. Shouldn't pg_sync_replication_slots() check whether the user has replication
> privilege?

Yes, added.

> 
> 2. The function declarations in slotsync.h don't seem to be in the same order as
> they are defined in slotsync.c. For example, see ValidateSlotSyncParams(). The
> same is true for new functions exposed via walreceiver.h and walsender.h. Please
> check the patch for other such inconsistencies.

I reordered the function declarations.

> 
> 3.
> +# Wait for the standby to finish sync
> +$standby1->wait_for_log(
> + qr/LOG: ( [A-Z0-9]+:)? newly created slot \"lsub1_slot\" is sync-ready
> +now/,  $offset);
> +
> +$standby1->wait_for_log(
> + qr/LOG: ( [A-Z0-9]+:)? newly created slot \"lsub2_slot\" is sync-ready
> +now/,  $offset);
> +
> +# Confirm that the logical failover slots are created on the standby
> +and are # flagged as 'synced'
> +is($standby1->safe_psql('postgres',
> + q{SELECT count(*) = 2 FROM pg_replication_slots WHERE slot_name IN
> ('lsub1_slot', 'lsub2_slot') AND synced;}),
> + "t",
> + 'logical slots have synced as true on standby');
> 
> Isn't the last test that queried pg_replication_slots sufficient? I think
> wait_for_log() would be required for slotsync worker or am I missing something?

I think it's not needed in 0001, so removed.

> Apart from the above, I have modified a few comments in the attached.

Thanks, it looks good to me, so applied.

Attach the V83 patch which addressed Peter[1][2], Amit and Sawada-san's[3]
comments. Only 0001 is sent in this version, we will send other patches after
rebasing.

[1] https://www.postgresql.org/message-id/CAHut%2BPvW8s6AYD2UD0xadM%2B3VqBkXP2LjD30LEGRkHUa-Szm%2BQ%40mail.gmail.com
[2] https://www.postgresql.org/message-id/CAHut%2BPv88vp9mNxX37c_Bc5FDBsTS%2BdhV02Vgip9Wqwh7GBYSg%40mail.gmail.com
[3] https://www.postgresql.org/message-id/CAD21AoDvyLu%3D2-mqfGn_T_3jUamR34w%2BsxKvYnVzKqTCpyq_FQ%40mail.gmail.com

Best Regards,
Hou zj

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).