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>, shveta malik <shveta.malik@gmail.com>
Cc: Peter Smith <smithpb2250@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Masahiko Sawada <sawada.mshk@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: 2024-01-29T13:47:35Z
Lists: pgsql-hackers 
On Monday, January 29, 2024 9:17 PM Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com> wrote:
> 
> On Monday, January 29, 2024 7:30 PM Amit Kapila <amit.kapila16@gmail.com>
> wrote:
> >
> > On Mon, Jan 29, 2024 at 3:11 PM shveta malik <shveta.malik@gmail.com>
> > wrote:
> > >
> > > PFA v71 patch set with above changes.
> > >
> >
> > Few comments on 0001
> 
> Thanks for the comments.
> 
> > ===================
> > 1.
> > parse_subscription_options()
> > {
> > ...
> > /*
> > * We've been explicitly asked to not connect, that requires some
> > * additional processing.
> > */
> > if (!opts->connect && IsSet(supported_opts, SUBOPT_CONNECT)) {
> >
> > Here, along with other options, we need an explicit check for
> > failover, so that if connect=false and failover=true, the statement
> > should give error. I was expecting the below statement to fail but it passed
> with WARNING.
> > postgres=# create subscription sub2 connection 'dbname=postgres'
> > publication pub2 with(connect=false, failover=true);
> > WARNING:  subscription was created, but is not connected
> > HINT:  To initiate replication, you must manually create the
> > replication slot, enable the subscription, and refresh the subscription.
> > CREATE SUBSCRIPTION
> 
> Added.
> 
> >
> > 2.
> > @@ -148,6 +153,10 @@ typedef struct Subscription
> >   List    *publications; /* List of publication names to subscribe to */
> >   char    *origin; /* Only publish data originating from the
> >   * specified origin */
> > + bool failover; /* True if the associated replication slots
> > + * (i.e. the main slot and the table sync
> > + * slots) in the upstream database are enabled
> > + * to be synchronized to the standbys. */
> >  } Subscription;
> >
> > Let's add this new field immediately after "bool runasowner;" as is
> > done for other boolean members. This will help avoid increasing the
> > size of the structure due to alignment when we add any new pointer
> > field in the future. Also, that would be consistent with what we do for other
> new boolean members.
> 
> Moved this field as suggested.
> 
> Attach the V72-0001 which addressed above comments, other patches will be
> rebased and posted after pushing first patch. Thanks Shveta for helping
> address the comments.

Apart from above comments. The new V72 patch also includes the followings changes.

1. Moved the test 'altering failover for enabled sub' to the tap-test where most
of the alter-sub behaviors are tested.

2. Rename the tap-test from 050_standby_failover_slots_sync.pl to
040_standby_failover_slots_sync.pl (the big number 050 was used to avoid
conflict with other newly committed tests). And add the test into meson.build
which was missed.

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).