| From: | Szymon Guz <mabewlun(at)gmail(dot)com> |
|---|---|
| To: | Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com> |
| Cc: | Marcin Mirosław <marcin(at)mejor(dot)pl>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: which one is faster |
| Date: | 2010-10-26 12:23:21 |
| Message-ID: | AANLkTikNYrEKhr=rFpGyEhgROv1wWE1XJk_ve1wtshCV@mail.gmail.com |
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| Lists: | pgsql-performance |
2010/10/26 Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com>
> 2010/10/26 Szymon Guz <mabewlun(at)gmail(dot)com>:
> >
> > Well, strange. Why is that slower?
>
> To answer that fully, you would need to see the implementation.
> suffice to say,
>
> count(a) does:
>
> if (a <> NULL)
> {
> count++;
> }
>
> and count(*) does:
>
> count++;
>
>
>
Yup, I was afraid of that, even if there is not null on the column... but I
think usually nobody notices the difference with count.
regards
Szymon
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