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help / color / mirror / Atom feedFrom: SATYANARAYANA NARLAPURAM <[email protected]>
To: Jeff Davis <[email protected]>
Cc: Bharath Rupireddy <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Disallow quorum uncommitted (with synchronous standbys) txns in logical replication subscribers
Date: Thu, 6 Jan 2022 23:55:01 -0800
Message-ID: <CAHg+QDc9sDR3mHBWpu6zyyUB75N2CXvA1Ntv-703yv61UHXrbg@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CALj2ACX-xO-ZenQt1MWazj0Z3ziSXBMr24N_X2c0dYysPQghrw@mail.gmail.com>
<CAHg+QDc-3bPT52yqB-_J-_8bc6DzpxVVzvQMA99XV_0tqOR9wg@mail.gmail.com>
<[email protected]>
On Thu, Jan 6, 2022 at 11:24 PM Jeff Davis <[email protected]> wrote:
> On Wed, 2022-01-05 at 23:59 -0800, SATYANARAYANA NARLAPURAM wrote:
> > I would like to propose a GUC send_Wal_after_quorum_committed which
> > when set to ON, walsenders corresponds to async standbys and logical
> > replication workers wait until the LSN is quorum committed on the
> > primary before sending it to the standby. This not only simplifies
> > the post failover steps but avoids unnecessary downtime for the async
> > replicas. Thoughts?
>
> Do we need a GUC? Or should we just always require that sync rep is
> satisfied before sending to async replicas?
>
I proposed a GUC to not introduce a behavior change by default. I have no
strong opinion on having a GUC or making the proposed behavior default,
would love to get others' perspectives as well.
>
> It feels like the sync quorum should always be ahead of the async
> replicas. Unless I'm missing a use case, or there is some kind of
> performance gotcha.
>
I couldn't think of a case that can cause serious performance issues but
will run some experiments on this and post the numbers.
>
> Regards,
> Jeff Davis
>
>
>
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected]
Subject: Re: Disallow quorum uncommitted (with synchronous standbys) txns in logical replication subscribers
In-Reply-To: <CAHg+QDc9sDR3mHBWpu6zyyUB75N2CXvA1Ntv-703yv61UHXrbg@mail.gmail.com>
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