Re: [PATCH] pg_dump: lock tables in batches - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [PATCH] pg_dump: lock tables in batches
Date
Msg-id 4040032.1670434083@sss.pgh.pa.us
Whole thread Raw
In response to Re: [PATCH] pg_dump: lock tables in batches  (Andres Freund <andres@anarazel.de>)
Responses Re: [PATCH] pg_dump: lock tables in batches  (Andres Freund <andres@anarazel.de>)
Re: [PATCH] pg_dump: lock tables in batches  (Fabrízio de Royes Mello <fabriziomello@gmail.com>)
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On 2022-12-07 10:44:33 -0500, Tom Lane wrote:
>> I have a strong sense of deja vu here.  I'm pretty sure I experimented
>> with this idea last year and gave up on it.  I don't recall exactly
>> why, but either it didn't show any meaningful performance improvement
>> for me or there was some actual downside (that I'm not remembering
>> right now).

> IIRC the case we were looking at around 989596152 were CPU bound workloads,
> rather than latency bound workloads. It'd not be surprising to have cases
> where batching LOCKs helps latency, but not CPU bound.

Yeah, perhaps.  Anyway my main point is that I don't want to just assume
this is a win; I want to see some actual performance tests.

> I wonder if "manual" batching is the best answer. Alexander, have you
> considered using libpq level pipelining?

I'd be a bit nervous about how well that works with older servers.

            regards, tom lane



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