On Oct 21, 2008, at 12:06 PM, Tom Lane wrote:
"Jim 'Decibel!' Nasby" <[EMAIL PROTECTED]> writes:WHERE 'xxxxxxxxxxx' IN (people.home_phone, people.work_phone, people.mobile_phone)Yeah, not exactly a common case, but at least in 8.1 this was turned into a set of ORs. Starting in 8.2 and in current HEAD, the planner turns that into:Filter: ('xxxxxxxxxxx'::text = ANY ((ARRAY[home_phone, mobile_phone, work_phone])::text[]))Which means automatic seqscan.It means no such thing.
It won't use an index scan on this query while it's in that form (even with enable_seqscan=off), but if I change it to a bunch of OR'd conditions it will switch to bitmap scans. The estimated cost with the seqscans is about 2x more expensive.
-- Decibel!, aka Jim C. Nasby, Database Architect [EMAIL PROTECTED] Give your computer some brain candy! www.distributed.net Team #1828
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