Tom Lane wrote:
> Benoit Delbosc<bdelbosc@xxxxxxxxx> writes:
>> On 13/04/2012 00:25, Tom Lane wrote:
>>> Is there a reason why you're writing the query in such a
>>> non-straightforward way, rather than just
>>>
>>> EXPLAIN ANALYZE SELECT hierarchy.id
>>> FROM hierarchy
>>> JOIN fulltext ON fulltext.id = hierarchy.id
>>> WHERE (TO_TSQUERY('whatever') @@ nx_to_tsvector(fulltext.fulltext))
>>> OR (TO_TSQUERY('whatever') @@ nx_to_tsvector(fulltext.fulltext_title));
>>
>> This query is written by a framework, also I thought that is a common
>> pattern that can be found in the documentation:
>> http://www.postgresql.org/docs/9.1/interactive/textsearch-controls.html
>
> Well, "common pattern" would be stretching it. Anyway I've concluded
> that this is in fact a planner bug. There will be a fix in 9.2, but I'm
> not going to take the risk of back-patching it, so you might want to
> think about changing that framework.
FYI the reason why we have queries that look like what Benoit
describes is that we often use the query alias twice, once for
TO_TSVECTOR and once for TS_RANK_CD, for instance:
SELECT hierarchy.id, TS_RANK_CD(fulltext, query1, 32) as nxscore
FROM hierarchy
JOIN fulltext ON fulltext.id = hierarchy.id,
TO_TSQUERY('whatever') query1,
TO_TSQUERY('whatever') query2
WHERE (query1 @@ nx_to_tsvector(fulltext.fulltext)) OR (query2 @@
nx_to_tsvector(fulltext.fulltext_title))
ORDER BY nxscore DESC;
(as is also described in the doc mentioned btw).
Florent
--
Florent Guillaume, Director of R&D, Nuxeo
Open Source, Java EE based, Enterprise Content Management (ECM)
http://www.nuxeo.com ; http://www.nuxeo.org ; +33 1 40 33 79 87
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