From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
Cc: | pgsql-docs(at)postgresql(dot)org |
Subject: | Re: Normalized Ranking example incorrect in text search |
Date: | 2007-11-14 19:37:22 |
Message-ID: | 11802.1195069042@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-docs |
Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> http://developer.postgresql.org/pgdocs/postgres/textsearch-controls.html
> Ranking Search Results
> shows and example which says
> "This is the same example using normalized ranking"
> and then gives a query which calculates normalization in an incorrect
> manner,
On what basis do you claim that's an incorrect manner? It's exactly
what is described in the paragraph just before the examples.
> A correct example
> would be something like this:
> SELECT title, ts_rank_cd(textsearch, query, 8 /*Normalization*/) AS rank
Why is that correct (or more correct than other ways)?
> - Can we say what the differences are between the two ranking functions?
> Why do we have two?
We already say that: the _cd function doesn't work without positional
info in the input tsvector.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2007-11-14 19:49:26 | Re: Normalized Ranking example incorrect in text search |
Previous Message | Jon Sime | 2007-11-14 17:29:27 | Re: Avoiding upgrade backlash |