Re: Static functions
| От | Gurjeet Singh |
|---|---|
| Тема | Re: Static functions |
| Дата | |
| Msg-id | 65937bea0810040714s30780c40g130fb1bfd038846a@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Static functions (Gregory Stark <stark@enterprisedb.com>) |
| Список | pgsql-general |
On Sat, Oct 4, 2008 at 6:06 PM, Gregory Stark <stark@enterprisedb.com> wrote:
Yup... I realized that after a bit of more testing after the mail... Immutable functions are single-call-per-command only of you are passing constants-only as parameters; if we have an expression involving columns, then they will be called for every row.
Best regards,
--
gurjeet[.singh]@EnterpriseDB.com
singh.gurjeet@{ gmail | hotmail | indiatimes | yahoo }.com
EnterpriseDB http://www.enterprisedb.com
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"Gurjeet Singh" <singh.gurjeet@gmail.com> writes:No, this is equally untrue for immutable.
> On Sat, Oct 4, 2008 at 8:49 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
>> "Gurjeet Singh" <singh.gurjeet@gmail.com> writes:
>> > Shouldn't PG make all efforts to not execute something when the result is
>> > already known?
>>
>> Not if said effort would cost more than is saved, which would be by far
>> the most likely result if we tried to cache all function results.
>>
>
> Sorry Tom, I confused STABLE with IMMUTABLE; my bad.
Yup... I realized that after a bit of more testing after the mail... Immutable functions are single-call-per-command only of you are passing constants-only as parameters; if we have an expression involving columns, then they will be called for every row.
Best regards,
--
gurjeet[.singh]@EnterpriseDB.com
singh.gurjeet@{ gmail | hotmail | indiatimes | yahoo }.com
EnterpriseDB http://www.enterprisedb.com
Mail sent from my BlackLaptop device
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