| From: | Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
|---|---|
| To: | Marc Millas <marc(dot)millas(at)mokadb(dot)com>, "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
| Cc: | "pgsql-general(at)lists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: locks within select |
| Date: | 2021-12-14 17:14:22 |
| Message-ID: | 86b7e09ff47c45f4455bc1421878ff33d505049c.camel@cybertec.at |
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| Thread: | |
| Lists: | pgsql-general |
On Tue, 2021-12-14 at 13:38 +0100, Marc Millas wrote:
> but... when you do setup a streaming replication, there is, in postgresql.conf, a variable:
> max_standby_streaming_delay = 30s # max delay before canceling queries when reading streaming WAL;
>
> as the secondary is, by nature, read only, I was wondering why it can be necessary to cancel a read request...
Perhaps this can explain some of what is going on:
https://www.cybertec-postgresql.com/en/streaming-replication-conflicts-in-postgresql/
Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com
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