Horton

Re: speed up a logical replica setup

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Euler Taveira <euler@eulerto.com>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>, "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com>, Peter Eisentraut <peter@eisentraut.org>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, Michael Paquier <michael@paquier.xyz>, Andres Freund <andres@anarazel.de>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Fabrízio de Royes Mello <fabriziomello@gmail.com>, vignesh C <vignesh21@gmail.com>
Date: 2024-04-30T08:47:54Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. pg_createsubscriber: Remove obsolete comment

  2. pg_createsubscriber: Fix an unpredictable recovery wait time.

  3. Fix unstable test in 040_pg_createsubscriber.

  4. Fix the testcase introduced in commit 81d20fbf7a.

  5. Further weaken new pg_createsubscriber test on Windows.

  6. Temporarily(?) weaken new pg_createsubscriber test on Windows.

  7. Make pg_createsubscriber warn if publisher has two-phase commit enabled.

  8. Make pg_createsubscriber more wary about quoting connection parameters.

  9. pg_createsubscriber: Remove failover replication slots on subscriber

  10. pg_createsubscriber: Remove replication slot check on primary

  11. pg_createsubscriber: Only --recovery-timeout controls the end of recovery process

  12. pg_createsubscriber: creates a new logical replica from a standby server

  13. Add some const decorations

  14. Add option force_initdb to PostgreSQL::Test::Cluster:init()

  15. Remove MSVC scripts

On Tue, Apr 30, 2024 at 12:04 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Mon, Apr 29, 2024 at 5:28 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Mon, Apr 29, 2024 at 5:23 PM Euler Taveira <euler@eulerto.com> wrote:
> >
>
> I was trying to test this utility when 'sync_replication_slots' is on
> and it gets in an ERROR loop [1] and never finishes. Please find the
> postgresql.auto used on the standby attached. I think if the standby
> has enabled sync_slots, you need to pass dbname in
> GenerateRecoveryConfig().

The other possibility is that when we start standby from
pg_createsubscriber, we specifically set 'sync_replication_slots' as
false.

>
> I couldn't test it further but I wonder if
> there are already synced slots on the standby (either due to
> 'sync_replication_slots' or users have used
> pg_sync_replication_slots() before invoking pg_createsubscriber),
> those would be retained as it is on new subscriber and lead to
> unnecessary WAL retention and dead rows.
>

This still needs some handling.

BTW, I don't see the use of following messages in --dry-run mode or
rather they could be misleading:
pg_createsubscriber: hint: If pg_createsubscriber fails after this
point, you must recreate the physical replica before continuing.
...
...
pg_createsubscriber: setting the replication progress (node name
"pg_0" ; LSN 0/0) on database "postgres"

Similarly, we should think if below messages are useful in --dry-run mode:
pg_createsubscriber: dropping publication
"pg_createsubscriber_5_887f7991" on database "postgres"
pg_createsubscriber: creating subscription
"pg_createsubscriber_5_887f7991" on database "postgres"
...
pg_createsubscriber: enabling subscription
"pg_createsubscriber_5_887f7991" on database "postgres"

-- 
With Regards,
Amit Kapila.