Re: Bad Estimate for complex query with JOINS on subselects and OR in where conditions

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: Bad Estimate for complex query with JOINS on subselects and OR in where conditions
Дата
Msg-id 11504.1565965540@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Bad Estimate for complex query with JOINS on subselects and OR in where conditions  (Peter Grman <peter.grman@gmail.com>)
Список pgsql-general
Peter Grman <peter.grman@gmail.com> writes:
> yes, I think this query is right below the geqo_threshold. But as I said,
> when I change only the WHERE condition to use AND instead of OR it's
> resulting in a really fast and efficient query (same planning time, but
> ~1/500th-1/1000th execution time). So there should be something different,
> or?

Don't really see why that would surprise you.  Using AND means that the
individual conditions can be applied as filters, if the planner knows
how to use any one of them as (say) an indexscan or join qual.  When
you use OR, that isn't possible.

            regards, tom lane



В списке pgsql-general по дате отправления:

Предыдущее
От: rob stone
Дата:
Сообщение: Re: A 3 table join question
Следующее
От: Rich Shepard
Дата:
Сообщение: Re: Variable constants ?