Message-ID: <938cf470050825d031f624b57f6ca46949304691.camel@cybertec.at>
Subject: Re: High latency and profiling
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Roberto Nunnari <robi@nunnari.ch>, pgsql-general@lists.postgresql.org
Date: Thu, 09 Oct 2025 21:21:19 +0200
In-Reply-To: <ea4bee5e-5d78-4209-b451-50fc5d860879@nunnari.ch>
References: <ea4bee5e-5d78-4209-b451-50fc5d860879@nunnari.ch>
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On Thu, 2025-10-09 at 19:25 +0200, Roberto Nunnari wrote:
> I was notified about high latency on one of our PostgreSQL clusters.
> This latency is observed from the application and has been increasing.=
=20
> There is no indication about the exact database as the application uses=
=20
> several DBs, but the largest and most used is 'mydb'.
>
> Developers report that their software is already optimized and database=
=20
> size is not a problem. They suggest the issue might be inside PostgreSQL=
=20
> itself.

That may be true, but it need not be true.  The developers' statement
sounds a bit overconfident.

> Could somebody help me understand what is causing the growing latency?

For that, you have to identify the statements that run longer than they
should.  Then examine them with EXPLAIN (ANALYZE, BUFFERS), figure out what
makes them slow and improve them.

Yours,
Laurenz Albe