[Please don't top post as it makes the discussion more difficult to
follow.]
On Aug 22, 2007, at 18:30 , Stephen Davies wrote:
I have always thought of array processing as the thing that vector
processors such as Cray and ETA do/did.
(I've always heard that referred to as vector processing.)
While superficially equivalent, I have always believed that IN (a,b,c)
executed faster than =a or =b or =c. Am I wrong for PostgreSQL?
Depending on the numbers of the IN list and other statistcs, I
believe PostgreSQL will rewrite z in IN (a, b, ...) into either (z =
a) OR (z = b) OR ... or somehow add it to the join list, so
performance will vary.
Michael Glaesemann
grzm seespotcode net
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
