Re: WIP: index support for regexp search - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: WIP: index support for regexp search
Date
Msg-id CAPpHfduFOqnVBXxNtT3SRSyy0ju4WKL6OY9sYqY6HQF+W0gGag@mail.gmail.com
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In response to Re: WIP: index support for regexp search  (Alexander Korotkov <aekorotkov@gmail.com>)
Responses Re: WIP: index support for regexp search  (Alexander Korotkov <aekorotkov@gmail.com>)
List pgsql-hackers
On Mon, Dec 3, 2012 at 4:31 PM, Alexander Korotkov <aekorotkov@gmail.com> wrote:
Actually, I generally dislike path matrix for same reasons. But:
1) Output graphs could contain trigrams which are completely useless for search. For example, for regex /(abcdefgh)*ijk/ we need only "ijk" trigram while graph would contain much more.Path matrix is a method to get rid of all of them.
2) If we use color trigrams then we need some criteria for which color trigrams to expand into trigrams. Simultaneously, we shouldn't allow path from initial state to the final by unexpanded trigrams. It seems much harder to do with graph than with matrix.

Now, I have an idea about doing some not comprehensive but simple and fast simplification of graph. I'm doing experiments now. In case of success we could get rid of path matrix.

------
With best regards,
Alexander Korotkov.

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