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Re: LIKE, leading percent, bind parameters and indexes

From: Martijn van Oosterhout <kleptog(at)svana(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>,Rodrigo Hjort <rodrigo(dot)hjort(at)gmail(dot)com>,Andrew Sullivan <ajs(at)crankycanuck(dot)ca>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: LIKE, leading percent, bind parameters and indexes
Date: 2006-05-29 06:52:13
Message-ID: 20060529065212.GA14432@svana.org (view raw or flat)
Thread:
Lists: pgsql-hackers
On Sat, May 27, 2006 at 11:52:40AM -0400, Tom Lane wrote:
> Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
> > How about the suggestion of using a sequential index scan like the
> > recent changes to VACUUM in the case that there are no regular index
> > quals?
> 
> Nonstarter (hint: the solution we found for VACUUM assumes there can
> be only one).

Bummer, I was envisioning allowing index AMs to have another access
method, the unordered sequential scan. Just like we consider a random
access of a real table to be more expensive than a seq scan, and index
scan that seeks a lot would be more expensive that a sequential scan.
So if you know you're going to scan most of an index, scanning
sequentially would be cheaper...

Ah well, 

Have a nice day,
-- 
Martijn van Oosterhout   <kleptog(at)svana(dot)org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

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