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Re: \d on database with a lot of tables is slow - Mailing list pgsql-hackers

From Tom Lane
Subject Re: \d on database with a lot of tables is slow
Date
Msg-id 9615.1128189612@sss.pgh.pa.us
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In response to Re: \d on database with a lot of tables is slow  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: \d on database with a lot of tables is slow  ("Jim C. Nasby" <jnasby@pervasive.com>)
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I wrote:
> It's presumably mostly in the pg_table_is_visible() calls.

I did some profiling on a test case with 10000 tables, and noticed that
a big part of the problem is that the catalog caches become entirely
useless: almost every catcache lookup ends up going to the underlying
tables.  This is because MAXCCTUPLES in catcache.c is fixed at 5000,
and that's not an adequate working set for this many tables.  If you
are willing to throw memory at the problem, you could try increasing
MAXCCTUPLES (to say 50K or 100K) and see if that helps.
        regards, tom lane

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