Re: Tsearch docs question

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Jeff Davis <pgsql(at)j-davis(dot)com>
Cc: pgsql-docs(at)postgresql(dot)org
Subject: Re: Tsearch docs question
Date: 2007-10-26 19:26:26
Message-ID: 24984.1193426786@sss.pgh.pa.us
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Jeff Davis <pgsql(at)j-davis(dot)com> writes:
> The Tsearch docs, under the GiST and GIN section, say:
> "Lossiness [of GiST] causes serious performance degradation since random
> access of heap records is slow and limits the usefulness of GiST
> indexes."

> The docs do go into some detail, but I think it causes some confusion,
> also.

Are you looking at CVS HEAD, or what was there in beta1? I rewrote
that stuff a few days ago:
http://developer.postgresql.org/pgdocs/postgres/textsearch-indexes.html

> There's also a related issue: I think a RECHECK would be less costly if
> you have the tsvectors materialized in the table (using triggers) and
> index that. Maybe that could be a tip for using GiST indexes.

Yeah, I mentioned that somewhere in the chapter, I think.

regards, tom lane

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