Re: bad estimates
| От | Ken Geis |
|---|---|
| Тема | Re: bad estimates |
| Дата | |
| Msg-id | 3F4F7A07.30404@speakeasy.org обсуждение исходный текст |
| Ответ на | Re: bad estimates (Bruno Wolff III <bruno@wolff.to>) |
| Ответы |
Re: bad estimates
|
| Список | pgsql-performance |
Bruno Wolff III wrote:
> If you want both the max and the min, then things are going to be a bit
> more work. You are either going to want to do two separate selects
> or join two selects or use subselects. If there aren't enough prices
> per stock, the sequential scan might be fastest since you only need to
> go through the table once and don't have to hit the index blocks.
>
> It is still odd that you didn't get a big speed up for just the min though.
I found I'm suffering from an effect detailed in a previous thread titled
Does "correlation" mislead the optimizer on large tables?
Ken
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