Re: We need index-only scans

Поиск
Список
Период
Сортировка
От Alvaro Herrera
Тема Re: We need index-only scans
Дата
Msg-id 1289573523-sup-7227@alvh.no-ip.org
обсуждение исходный текст
Ответ на Re: We need index-only scans  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Список pgsql-hackers
Excerpts from Heikki Linnakangas's message of vie nov 12 11:01:39 -0300 2010:

> It took me a while to understand what Greg meant as well. You can't scan 
> a B-tree index in *physical order*, You have to first descend to the 
> leftmost leaf, and follow the right pointers from there until you reach 
> the rightmost leaf. That is a lot slower than seqscanning a file in 
> physical order.

Oh, that makes more sense.  I'm not sure that can be supported sanely
(i.e. not locking the whole index)

-- 
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: MULTISET and additional functions for ARRAY
Следующее
От: Tom Lane
Дата:
Сообщение: Re: Re: [BUGS] BUG #5650: Postgres service showing as stopped when in fact it is running