Re: Speed of exist

Поиск
Список
Период
Сортировка
От Bastiaan Olij
Тема Re: Speed of exist
Дата
Msg-id 5123518F.30206@basenlily.me
обсуждение исходный текст
Ответ на Re: Speed of exist  (Pavel Stehule <pavel.stehule@gmail.com>)
Список pgsql-performance
Hi Pavel,

That is what I've done in this particular case but there are parts where
I use exist checks in this way that are very cumbersome to write out
like that so I'm hoping there is a way to make the optimizer work with
existence checks in this way.

Cheers,

Bastiaan Olij

On 19/02/13 6:39 PM, Pavel Stehule wrote:
> 2013/2/19 Bastiaan Olij <bastiaan@basenlily.me>:
>> Hi Andy,
>>
>> I've tried that with the same result. One subquery works beautifully,
>> two subqueries with an OR and it starts to do a sequential scan...
> try to rewrite OR to two SELECTs joined by UNION ALL
>
> Pavel
>



В списке pgsql-performance по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: slow query plans caused by under-estimation of CTE cardinality
Следующее
От: Josh Berkus
Дата:
Сообщение: Re: High CPU usage / load average after upgrading to Ubuntu 12.04