|From:||Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>|
|Subject:||Re: contsel and gist|
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Ben <midfield(at)gmail(dot)com> writes:
> my guess is that it has to do with the selectivity of the @> operator. i've looked and noticed that the selectivity functions for @> and other period operators are basically stubs, with constant selectivity. my questions are :
> 1 - am i wrong in my assessment? is the constant contsel, areasel, etc hurting us?
The stub selectivity functions definitely suck.
> 2 - how hard would it be to implement contsel et al for period data types?
If it were easy, it'd likely have been done already :-(
However, having said that: the constant value of the stub contsel
function is intended to be small enough to encourage use of an
indexscan. Maybe we just need to decrease it a bit more. Have you
investigated what the cutover point is for your queries?
regards, tom lane
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