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Date: Wed, 06 Jun 2007 23:23:13 +0100
From: James Mansion <james@mansionfamily.plus.com>
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To: mark@mark.mielke.cc
CC: Mark Lewis <mark.lewis@mir3.com>, Magnus Hagander <magnus@hagander.net>,
	Alexander Staubo <alex@purefiction.net>, Andy <frum@ar-sd.net>,
	pgsql-performance@postgresql.org
Subject: Re: LIKE search and performance
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mark@mark.mielke.cc wrote:
> What is a real life example where an intelligent and researched
> database application would issue a like or ilike query as their
> primary condition in a situation where they expected very high
> selectivity?
>   
In my case the canonical example is to search against textual keys where 
the search is
performed automatically if the user hs typed enough data and paused.  In 
almost all
cases the '%' trails, and I'm looking for 'starts with' in effect.  
usually the search will have
a specified upper number of returned rows, if that's an available 
facility.  I realise in this
case that matching against the index does not allow the match count 
unless we check
MVCC as we go, but I don't see why another thread can't be doing that.

James