Re: Full Text Inverted Indexes

From: Marc Tardif <intmktg_at_Gloria.CAM.ORG>
Date: 2000/06/13
Message-ID: <Pine.LNX.4.10.10006131315570.16439-100000_at_Gloria.CAM.ORG>#1/1


Put simply, a trigger is compiled which converts a string such as 'usenet' to a new full text index table: oid | string
----+--------

123 | usenet
123 |  senet
123 |   enet
123 |    net
123 |     et

where oid is the object identifier of the row containing 'usenet'. So when you want to find rows containing 'net', you would normally search for '%net%' whereas you can now search for 'net%' which uses an index scan instead of a sequential scan. Since this is done using a trigger, your code only needs to change the queries to the sql table.

If you have access to the web, you can grab the code from one of the many ftp sites available. See: http://www.postgresql.org/sites.html

On Mon, 12 Jun 2000, christos christou wrote:

> Hi,
>
> can you please explain in brief how they implement the full text index in
> PostgreSQL and how they do partial matching?? i don't have access to the
> PostgreSQL source code.
>
> thanks.
>
> Marc Tardif wrote:
>
> > See the contrib directory in the PostgreSQL source code. It has an example
> > for implementing a full text index as a trigger which make partial
> > matchting much quicker.
> >
> > On Thu, 8 Jun 2000, Lewis wrote:
> >
> > > Hello,
> > >
> > > I want to learn how to create a full text indexer. Does anyone know of a
> > > good source that explains them in detail?
> > >
> > > Thanks for any help
> > > Randall
> > >
> > >
> > >
> > >
> > >
>
>
>
Received on Tue Jun 13 2000 - 00:00:00 CEST

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