Oliver Snowden wrote:
Dear all, I am having some problems with a bad query plan. Essentially,
I have two tables. A table of many different types of geography and
another table (reports) linking to those geographies. We want to select
a small subset of reports (e.g. 30 reports) based on date and intersect
those report geographies (potentially historical geographies) with a
(current) selected geography.
I have (conceptually) worked out what I believe to be most efficient by
putting the query into canonical form, moving the restricts down and
putting the most restrictive item first; although I haven't actually
done any specific calculations - index/disk access speeds etc.
My view is that the query should be executed as shown below.
Any comments or suggestions will be greatly appreciated. We have tried
various things inc. subqueries, using &&, and indexing almost everything
etc. Still no luck.
Many thanks, Oliver.
Hi Oliver,
Please can we see the EXPLAIN ANALYZE output for queries STEP 3 and STEP 4?
Many thanks,
Mark.
--
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063
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