| From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, zotov(at)oe-it(dot)ru, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Bad plan when join on function |
| Date: | 2011-01-17 21:37:01 |
| Message-ID: | AANLkTim33Of+Xy+wRMBGx=HZOi_8VFqLXrXyE+5qrJqv@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
2011/1/17 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
>> it should to work without functional index - but not sure about effectivity
>
> As long as the function is VOLATILE, the planner can't use any
> intelligent query plan. Merge or hash join both require at least
> stable join keys.
sure, my first advice was a question about function volatility - and
my sentence was related to using immutable function.
regards
Pavel Stehule
>
> regards, tom lane
>
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Mladen Gogala | 2011-01-17 22:11:09 | Re: Possible to improve query plan? |
| Previous Message | Tom Lane | 2011-01-17 21:33:44 | Re: Bad plan when join on function |