Re: Proposal: q-gram GIN and GiST indexes

From: Alexander Korotkov <aekorotkov(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Proposal: q-gram GIN and GiST indexes
Date: 2011-04-05 12:09:49
Message-ID: BANLkTi=5tQGXk2d1AE-iTg_O_+_1qP+98g@mail.gmail.com
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On Tue, Apr 5, 2011 at 3:56 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> So with q=5, the index will be approximately 10x larger than with q=3.
> Maybe that's OK, I'm not sure. But it is a big difference.

Not whole index will be approximately 10x larger, but only entries pages
number (which contains btree on gin keys, i.e. q-grams), while data pages
number (which contains links to rows in lists or btrees) will be similar. In
dependence on data volume index size can be 10x larger (on small datasets)
or few percents larger (on large datasets).

----
With best regards,
Alexander Korotkov.

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