Re: Any better plan for this query?..
От | Simon Riggs |
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Тема | Re: Any better plan for this query?.. |
Дата | |
Msg-id | 1242732985.14551.188.camel@ebony.2ndQuadrant обсуждение исходный текст |
Ответ на | Re: Any better plan for this query?.. (Matthew Wakeling <matthew@flymine.org>) |
Ответы |
Re: Any better plan for this query?..
Re: Any better plan for this query?.. Re: Any better plan for this query?.. |
Список | pgsql-performance |
On Tue, 2009-05-19 at 12:17 +0100, Matthew Wakeling wrote: > Yes, Postgres has been missing the boat on this one for a while. +1 on > requesting this feature. That's an optimizer feature. > Speaking of avoiding large sorts, I'd like to push again for partial > sorts. This is the situation where an index provides data sorted by > column "a", and the query requests data sorted by "a, b". Currently, > Postgres sorts the entire data set, whereas it need only group each > set of identical "a" and sort each by "b". This is an executor feature. Partially sorted data takes much less effort to sort (OK, not zero, I grant) so this seems like a high complexity, lower value feature. I agree it should be on the TODO, just IMHO at a lower priority than some other features. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support
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