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Re: How Postgresql Compares... Count(*) and others - Mailing list pgsql-general

From Tom Lane
Subject Re: How Postgresql Compares... Count(*) and others
Date
Msg-id 499.995773781@sss.pgh.pa.us
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In response to How Postgresql Compares... Count(*) and others  (Mark kirkwood <markir@slingshot.co.nz>)
Responses Re: How Postgresql.... Putting Count(*) To Bed (Hopefully)  (Mark kirkwood <markir@slingshot.co.nz>)
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Mark kirkwood <markir@slingshot.co.nz> writes:
> I have not tried to see if it makes any difference in Postgresql...

Postgres converts count(*) to count(1) at the grammar stage (cf. gram.y,
about line 4817 in current sources).  So if you think you detect any
performance difference, you're surely hallucinating...

            regards, tom lane

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