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Re: PostgreSQL clustering VS MySQL clustering

From: Hannu Krosing <hannu(at)tm(dot)ee>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>,Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, marty(at)outputservices(dot)com,herve(at)elma(dot)fr, pgsql-performance(at)postgresql(dot)org
Subject: Re: PostgreSQL clustering VS MySQL clustering
Date: 2005-01-26 09:41:18
Message-ID: 1106732479.5587.4.camel@fuji.krosing.net (view raw or flat)
Thread:
Lists: pgsql-performance
Ühel kenal päeval (teisipäev, 25. jaanuar 2005, 10:41-0500), kirjutas
Tom Lane:
> Hannu Krosing <hannu(at)tm(dot)ee> writes:
> > Why is removing index entries essential ?
> 
> Because once you re-use the tuple slot, any leftover index entries would
> be pointing to the wrong rows.

That much I understood ;)

But can't clearing up the index be left for "later" ? 

Indexscan has to check the data tuple anyway, at least for visibility.
would adding the check for field sameness in index and data tuples be
too big performance hit ?

> 			regards, tom lane
> 
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-- 
Hannu Krosing <hannu(at)tm(dot)ee>

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