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: 2024-04-29T09:56:48Z
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 Wed, Mar 27, 2024 at 1:47 AM Euler Taveira <euler@eulerto.com> wrote:
>
> On Tue, Mar 26, 2024, at 4:12 PM, Tomas Vondra wrote:
>
> Perhaps I'm missing something, but why is NUM_CONN_ATTEMPTS even needed?
> Why isn't recovery_timeout enough to decide if wait_for_end_recovery()
> waited long enough?
>
>
> It was an attempt to decoupled a connection failure (that keeps streaming the
> WAL) from recovery timeout. The NUM_CONN_ATTEMPTS guarantees that if the primary
> is gone during the standby recovery process, there is a way to bail out.
>

I think we don't need to check primary if the WAL corresponding to
consistent_lsn is already present on the standby. Shouldn't we first
check that? Once we ensure that the required WAL is copied, just
checking server_is_in_recovery() should be sufficient. I feel that
will be a direct way of ensuring what is required rather than
indirectly verifying the same (by checking pg_stat_wal_receiver) as we
are doing currently.

-- 
With Regards,
Amit Kapila.