From: James Mansion <james@mansionfamily.plus.com>
To: mark@mark.mielke.cc
Cc: Mark Lewis <mark.lewis@mir3.com>
Cc: Magnus Hagander <magnus@hagander.net>
Cc: Alexander Staubo <alex@purefiction.net>
Cc: Andy <frum@ar-sd.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: LIKE search and performance
Date: Wed, 06 Jun 2007 23:23:13 +0100
Message-ID: <466733D1.1040308@mansionfamily.plus.com> (raw)
In-Reply-To: <20070524215450.GA3858@mark.mielke.cc>
References: <009501c79d4c$445428f0$0b00a8c0@mpsro.dom>
<88daf38c0705230905u1a981102k691b47bd36011a80@mail.gmail.com>
<4655DE75.4080506@mansionfamily.plus.com>
<4655E64B.5050503@hagander.net>
<4655FB8A.1040707@mansionfamily.plus.com>
<1180040560.31471.262.camel@archimedes>
<20070524215450.GA3858@mark.mielke.cc>
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
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To: pgsql-performance@postgresql.org
Cc: james@mansionfamily.plus.com, mark@mark.mielke.cc, mark.lewis@mir3.com, magnus@hagander.net, alex@purefiction.net, frum@ar-sd.net
Subject: Re: LIKE search and performance
In-Reply-To: <466733D1.1040308@mansionfamily.plus.com>
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