Horton

Re: Synchronizing slots from primary to standby

Amit Kapila <amit.kapila16@gmail.com>

View thread View on postgr.es
From: Amit Kapila <amit.kapila16@gmail.com>
To: shveta malik <shveta.malik@gmail.com>
Cc: Peter Smith <smithpb2250@gmail.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.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: 2024-01-29T11:30:29Z
Lists: pgsql-hackers 
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
===================
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

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.

-- 
With Regards,
Amit Kapila.

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).