Re: Planner hints in Postgresql

Atri Sharma <atri(dot)jiit(at)gmail(dot)com> writes:
> On Mon, Mar 17, 2014 at 9:45 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Possibly worth noting is that in past discussions, we've concluded that
>> the most sensible type of hint would not be "use this plan" at all, but
>> "here's what to assume about the selectivity of this WHERE clause".
>> That seems considerably less likely to break than any attempt to directly
>> specify plan details.

> Isnt using a user given value for selectivity a pretty risky situation as
> it can horribly screw up the plan selection?

And forcing a plan to be used *isn't* that? Please re-read the older
threads, since you evidently have not.

regards, tom lane