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Re: Possible interesting extra information for explain analyze?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Jeff <threshar(at)torgo(dot)978(dot)org>
Cc: performance pgsql <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Possible interesting extra information for explain analyze?
Date: 2005-02-25 16:05:10
Message-ID: 5599.1109347510@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-performance
Jeff <threshar(at)torgo(dot)978(dot)org> writes:
> Given some recent posts / irc issues with dead tuple bloat..
> And given that a lot of these people have at least been smart enough to 
> explain analyze would it be A. possible B. useful C. None of the above 
> to have various "scan" nodes of explain analyze also report how many 
> invisible / dead tuples they had to disqualify (Just to clarify, they 
> matched the search criteria, but were invisible due to MVCC rules).  

I think this would not help a whole lot because (particularly on
indexscans) you won't get a very accurate picture of the true extent
of bloat.  The contrib/pgstattuple utility is more useful for measuring
that sort of thing.

			regards, tom lane

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