Is is possible to persuade the query planner that ~* operations are grossly
expensive - or at least much more expensive than some other operations.
My reason is that I have a databsase on which we do a lot of queries of the
form
SELECT
*
FROM
primary_table
secondary_table as t1
secondary_table as t2
WHERE primary_table.id = t1.id
AND primary_table.id = t2.id
AND t1.col1 = 1
AND t2.col1 = 2
AND primary_table.blob ~* 'wibble';
unfortunately the query optimiser always tries to do the ~* operator before
it has done the other (more selective) queries, and over 100,000+ rows this
is very slow.
So, can I force the query optimizer to delay doing the ~* until after the
selective joins?
--
Nick Howden - Senior IT Analyst
QinetiQ Trusted Information Management
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