Re: Full Text Index disk space requirements - Mailing list pgsql-performance

From Maarten Boekhold
Subject Re: Full Text Index disk space requirements
Date
Msg-id T5eccd06734c407b7066f0@reuters.com
Whole thread Raw
In response to Full Text Index disk space requirements  (<typea@l-i-e.com>)
Responses Re: Full Text Index disk space requirements
Re: Full Text Index disk space requirements
List pgsql-performance
Hi,

if memory serves me right, the space requirements for this would be
something like:

        42 (per tuple overhead)
        4 (size of OID?)
        16 (substitute with the maximum length of any 'string' in your
fulltext.sorted)
+ -------------
        62
        20,000,000 (substitute with number of lines in fulltext.sorted,
i.e. 'wc -l fulltext.sorted')
*---------------------------
        1,240,000,000

or about 1.2G?

or
On 11/26/2002 01:36:59 PM typea wrote:
> Wouldn't using f1.string = 'perth' be faster than f1.string ~ '^perth'
and
> equally useful?  Or is ~ with ^ somehow actually faster than the
seemingly
> simple = comparison?

f1.string = 'perth' would only match 'perth', while f1.string ~ '^perth'
would also match 'perthinent' (yes, I know this word does not exist).

Maarten

ps. are you trying to use the stuf from the 'fulltextindex' directory in
contrib/? I originally wrote this as an experiment, and it actually turned
out not to be fast enough for my purpose. I've never done anything with
full text indexing again, but I believe that currently there are better
solutions based on PostgreSQL (i.e. OpenFTI?)


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