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Re: Proposal: q-gram GIN and GiST indexes

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Alexander Korotkov <aekorotkov(at)gmail(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Proposal: q-gram GIN and GiST indexes
Date: 2011-04-04 17:01:38
Message-ID: BANLkTimW4jYwh33P8DPF_VBBmc7v5wCMAQ@mail.gmail.com (view raw or flat)
Thread:
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On Mon, Apr 4, 2011 at 12:38 PM, Alexander Korotkov
<aekorotkov(at)gmail(dot)com> wrote:
> relatively small when q <= 5. Accordingly, I think we should expect indexes
> to be usable with at least with q = 5.

I defer to your opinion on this, since you know more about it than I
do.  But I think it would still be worthwhile to write a quick Perl
script and calculate the number q-grams in various sample texts for
various values of q.  The worst case is surely exponential in q, so
it'd be nice to have some evidence of what the real-world behavior is.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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