Re: [HACKERS] Help: fmgr_info: function 0: cache lookup failed

Tom, was this dealth with?

> "D'Arcy" "J.M." Cain <darcy@druid.net> writes:
> >>>> I tried just setting oprcanhash to true but that didn't do it.  Can
> >>>> you suggest what fields I need to look at in pg_operator?
> >> 
> >> oprrest and oprjoin
> 
> > OK, I did this and it worked.  I'll go work on the documentation now.
> 
> OK, I see the problem: btreesel() and friends blithely assume that the
> operator used in an index will have a selectivity function (oprrest).
> 
> I can see two reasonable fixes:
>   * Default to an 0.5 estimate if no oprrest link (this is what the
>     optimizer does for operators that have no oprrest).
>   * Generate an error message along the lines of "index operators must
>     have a restriction selectivity estimator", if we think that they
>     really really oughta.
> 
> I'm not sure which way to jump.  The former would be more friendly for
> people just starting to develop index support for a new data type ...
> but then they might never realize that lack of an estimator is hurting
> performance for them.  Comments?
> 
>             regards, tom lane
> 
> 


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