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Re: planner/optimizer question

From: "Gary Doades" <gpd(at)gpdnet(dot)co(dot)uk>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: planner/optimizer question
Date: 2004-04-28 07:08:03
Message-ID: 408F6663.22977.CC6AF7D@localhost (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
I can understand the performance loss on non-selects for keeping the 
index validity state tracking the row validity, but would that outweigh the 
performance gains on selects? Depends on your mix of selects to non 
selects I guess, but other database systems seem to imply that keeping 
the index on track is worth it overall.


On 28 Apr 2004 at 15:04, Christopher Kings-Lynne wrote:

> > Why is there an entry in the index for a row if the row is not valid? 
> > Wouldn't it be better for the index entry validity to track the row validity. 
> > If a particular data value for a query (join, where etc.) can be satisfied 
> > by the index entry itself this would be a big performance gain.
> For SELECTs, yes - but for INSERT, UPDATE and DELETE it would be a big 
> performance loss.
> Chris

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