Output of explain (and as likely, explain analyze) for this would be helpful. A On Wed, Mar 16, 2011 at 10:49:24AM -0500, Davenport, Julie wrote: > When I run the following query in Postgres 8.0, it runs in 61,509.372 ms > > When I run it in Postgres 8.4, it runs in 397,857.472 ms > > Here is the query: > > select > course_id AS EXTERNAL_COURSE_KEY, > user_id AS EXTERNAL_PERSON_KEY, > 'Student' AS ROLE, > 'Y' AS AVAILABLE_IND > from course_user_link > where instructor = false > and course_id in > ( > select course_id > from course_control > where to_char(course_begin_date,'YYYYMMDD') IN ( '20100412','20100510','20100607','20100712','20100830','20100927','20101025','20101122','20101213','20110110','20110207','20110307' ) > and course_delivery LIKE 'O%' > and course_cross_section IS NULL > ) > and user_id not in (select user_id from instr_as_stutemp) > > (table instr_as_stutemp has just one column and only 4 rows) > > What new feature of Postgres 8.4 would be making the query run so much more slowly? Is there a better way to rewrite the query for 8.4 to make it run faster? > > Many thanks, > Julie -- Andrew Sullivan ajs@xxxxxxxxxxxxxxx -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
