Tom Lane wrote:
"Atul Deopujari" <[EMAIL PROTECTED]> writes:
Yes, letting the planner make its own decision would seem best (in
accordance with what we do for different join paths). But for large IN
lists, a substantial part of the planner is spent in estimating the
selectivity of the ScalarArrayExpr by calling scalararraysel. If we are
not eliminating this step in processing the IN list then we are not
doing any optimization. Asking the planner to do scalararraysel and also
compute cost of any other way and choose between the two is asking
planner to do more work.
So? Better planning usually involves more work. In any case the above
argument seems irrelevant, because making scalararraysel more
approximate and less expensive for long lists could be done
independently of anything else.
Got you and agree with you.
--
Atul
EnterpriseDB
www.enterprisedb.com
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