Re: Select max(primary_key) taking a long time

Поиск
Список
Период
Сортировка
От Merlin Moncure
Тема Re: Select max(primary_key) taking a long time
Дата
Msg-id AANLkTikXvscy5qkI3Nlt0rGiw2JcIYevb4LPiCcBf-5N@mail.gmail.com
обсуждение исходный текст
Ответ на Re: Select max(primary_key) taking a long time  (Francisco Reyes <lists@stringsutils.com>)
Список pgsql-general
On Fri, May 21, 2010 at 1:48 PM, Francisco Reyes <lists@stringsutils.com> wrote:
> Tom Lane writes:
>
>> Francisco Reyes <lists@stringsutils.com> writes:
>>>
>>> I am trying to do
>>> select max(primary_key) from some_table;
>>
>> Are there a whole lot of nulls in that column?
>
>
> Zero nulls. It is a primary key.

do a big delete recently?  any other open transactions?  since you are
i/o waiting, I'm guessing either hint bits or you have another
transaction in play which established tons of rows that your query has
to wade through...

the remedy for the former is to simply eat it (one time penalty) or
rebuild the table.  for the latter you simply have to resolve the
other transaction.

how big is your table according to pg_relation_size()?

merlin

В списке pgsql-general по дате отправления:

Предыдущее
От: Merlin Moncure
Дата:
Сообщение: Re: Help reqd on azimuth finction
Следующее
От: erobles
Дата:
Сообщение: Re: NOTICE: ignoring incomplete trigger group for constraint