Re: response time is very long in PG9.5.5 using psql or jdbc - Mailing list pgsql-bugs

From Andres Freund
Subject Re: response time is very long in PG9.5.5 using psql or jdbc
Date
Msg-id 20180213213110.5ip4hsnu2hjz52ae@alap3.anarazel.de
Whole thread Raw
In response to Re: response time is very long in PG9.5.5 using psql or jdbc  (David Gould <daveg@sonic.net>)
Responses Re: response time is very long in PG9.5.5 using psql or jdbc  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: response time is very long in PG9.5.5 using psql or jdbc  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
List pgsql-bugs
Hi,

On 2018-02-13 13:24:47 -0800, David Gould wrote:
> I see this problem fairly frequently. Typically the problem catalog is
> pg_attribute as it has the most rows. However the problem really arises when
> the catalogs become bloated. Once the total size of the catalogs that get
> read at start up approaches the size of shared buffers, and especially if
> several processes start at the same time, it becomes quite noticeable.

I can obviously see problems with a bloated catalog, but how does that
cause massive slowdowns in *individual* queries as we see here?  The
OP's problem isn't the connection establishment performance afaict, but
the first query using specific pieces of catalog data. And that should
be ok-ish performancewise, even if there's bloat.

Greetings,

Andres Freund


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