Re: Inaccuracy in VACUUM's tuple count estimates

From: tim_wilson <tim(dot)wilson(at)telogis(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Inaccuracy in VACUUM's tuple count estimates
Date: 2014-06-26 00:42:51
Message-ID: 1403743371788-5809273.post@n5.nabble.com
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Given that this seems to have slipped off the hackers radar (or in too hard
basket) I have constructed a horrible solution.

I will stop using autovacuum for this relation , I will use our own system
to monitor the relation, and I will reset pgclass.reltuples on this relation
after vacuum is done to the correct value.

I note that vacuum.c has comments in vac_update_relstat that changes to
pg_class are done without a transaction. Are there dangers of my doing an
update pg_class set reltuples=60000 where relkind='r' and
relname='my_hot_table' ?

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