Re: another query optimization question

От: Tom Lane
Тема: Re: another query optimization question
Дата: ,
Msg-id: 3875.1075563956@sss.pgh.pa.us
(см: обсуждение, исходный текст)
Ответ на: Re: another query optimization question  (David Teran)
Ответы: Re: another query optimization question  ("Marc G. Fournier")
Список: pgsql-performance

Скрыть дерево обсуждения

another query optimization question  (David Teran, )
 Re: another query optimization question  (PC Drew, )
 Re: another query optimization question  (Stephan Szabo, )
  Re: another query optimization question  (David Teran, )
   Re: another query optimization question  (Tom Lane, )
    Re: another query optimization question  (Richard Huxton, )
    Re: another query optimization question  (David Teran, )
     Re: another query optimization question  (Tom Lane, )
      Re: another query optimization question  (David Teran, )
       Re: another query optimization question  (Tom Lane, )
        Re: another query optimization question  ("Marc G. Fournier", )
         Re: another query optimization question  (David Teran, )

David Teran <> writes:
> Apple provides a little tool that can enable / disable the l2 cache ...
> one CPU of a dual CPU system on the fly. When i start the testapp with
> two CPU's enabled i get this output here, when i turn off one CPU while
> the app is still running the messages disappear as long as one CPU is
> turned off. Reactivating the CPU again produces new error messages.

Ah-hah, so the gettimeofday bug *is* linked to multiple CPUs.  Marc,
were the machines you saw it on all multi-CPU?

> Do you remember where one can find a patch?

File a bug report with Apple.

> Do you know if this bug makes a system unusable with PostgresSQL?

Not at all.  The only bad effect we've noted is that EXPLAIN results
are sometimes wacky.  In theory you could sometimes see the result of
now() being off by a second or two, but no one's reported seeing that.

            regards, tom lane


В списке pgsql-performance по дате сообщения:

От: David Teran
Дата:
Сообщение: Re: another query optimization question
От: Richard Huxton
Дата:
Сообщение: Re: views?