Re: Increasing GROUP BY CHAR columns speed

От: Andrus
Тема: Re: Increasing GROUP BY CHAR columns speed
Дата: ,
Msg-id: 2B43ECEF2E3A49A1811782BD8FD8E67E@andrusnotebook
(см: обсуждение, исходный текст)
Ответ на: Increasing GROUP BY CHAR columns speed  ("Andrus")
Список: pgsql-performance

Скрыть дерево обсуждения

Increasing GROUP BY CHAR columns speed  ("Andrus", )
 Re: Increasing GROUP BY CHAR columns speed  (Scott Carey, )
  Re: Increasing GROUP BY CHAR columns speed  ("Andrus", )
   Re: Increasing GROUP BY CHAR columns speed  ("Scott Marlowe", )
    Re: Increasing GROUP BY CHAR columns speed  (Scott Carey, )
     Re: Increasing GROUP BY CHAR columns speed  ("Andrus", )
     Re: Increasing GROUP BY CHAR columns speed  ("Andrus", )
     Re: Increasing GROUP BY CHAR columns speed  ("Scott Marlowe", )
     Re: Increasing GROUP BY CHAR columns speed  ("Andrus", )
      Re: Increasing GROUP BY CHAR columns speed  ("Greg Stark", )
 Re: Increasing GROUP BY CHAR columns speed  ("Andrus", )

>I it seems that slowness is caused by grouping by column
>
> exchrate numeric(13,8)

exchrate has different values in few rows.
It has usually value 0
In this sample query it is always 0.

I tried not change exchrate with

nullif( bilkaib.EXCHRATE,0)

but this does not up speed query, no idea why.

Andrus.


В списке pgsql-performance по дате сообщения:

От: "Kevin Grittner"
Дата:
Сообщение: Re: Memory Allocation
От: "Andrus"
Дата:
Сообщение: Re: Increasing GROUP BY CHAR columns speed