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Re: Much Ado About COUNT(*)

From: "Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>
To: Rod Taylor <pg(at)rbt(dot)ca>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Much Ado About COUNT(*)
Date: 2005-01-12 20:59:07
Message-ID: 41E58F9B.60600@tvi.edu (view raw or flat)
Thread:
Lists: pgsql-announcepgsql-hackerspgsql-patches
Rod Taylor wrote:

>
>grow by about 40GB if this was done. Storage isn't that cheap when you
>include the hot-backup master, various slaves, RAM for caching of this
>additional index space, backup storage unit on the SAN, tape backups,
>additional spindles required to maintain same performance due to
>increased IO because I don't very many queries which would receive an
>advantage (big one for me -- we started buying spindles for performance
>a long time ago), etc.
>  
>
Thanks for the calculation and example.  This would be a hefty amount of 
overhead if none of your queries would benefit from this change.

>Make it a new index type if you like, but don't impose any new
>performance constraints on folks who have little to no advantage from
>the above proposal.
>  
>
I agree with you that some people may not see any benefit from this and 
that it may look worse performance/storage-wise.  I've considered this 
route, but it seems like more of a workaround than a solution.



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