Re: Performance under contention

Список
Период
Сортировка
От Kevin Grittner
Тема Re: Performance under contention
Дата
Msg-id 4CECD0E50200002500037DE2@gw.wicourts.gov
обсуждение исходный текст
Ответ на Re: Performance under contention  (Vitalii Tymchyshyn)
Список pgsql-performance
Дерево обсуждения
Performance under contention  (Ivan Voras, )
 Re: Performance under contention  ("Kevin Grittner", )
  Re: Performance under contention  (Ivan Voras, )
   Re: Performance under contention  (Jignesh Shah, )
    Re: Performance under contention  (Omar Kilani, )
   Re: Performance under contention  ("Kevin Grittner", )
    Re: Performance under contention  (Ivan Voras, )
     Re: Performance under contention  (Craig Ringer, )
      Re: Performance under contention  (Ivan Voras, )
      Re: Performance under contention  (Vitalii Tymchyshyn, )
       Re: Performance under contention  ("Kevin Grittner", )
 Re: Performance under contention  ("Kevin Grittner", )
  Re: Performance under contention  (Ivan Voras, )
 Re: Performance under contention  (Greg Smith, )
  Re: Performance under contention  (Ivan Voras, )
 Re: Performance under contention  (Robert Haas, )
  Re: Performance under contention  (Robert Haas, )
  Re: Performance under contention  (Jignesh Shah, )
   Re: Performance under contention  (Jignesh Shah, )
   Re: Performance under contention  (Robert Haas, )
    Re: Performance under contention  (Tom Lane, )
     Re: Performance under contention  (Dave Crooke, )
     Re: Performance under contention  (Robert Haas, )
    Re: Performance under contention  (Ivan Voras, )
     Re: Performance under contention  (Robert Haas, )
      Re: Performance under contention  (Ivan Voras, )
      Re: Performance under contention  (Віталій Тимчишин, )
       Re: Performance under contention  (Ivan Voras, )
       Re: Performance under contention  (Robert Haas, )
        Re: Performance under contention  (Robert Haas, )
         Re: Performance under contention  (Tom Lane, )
          Re: Performance under contention  (Robert Haas, )
           Re: Performance under contention  (Tom Lane, )
            Re: Performance under contention  (Robert Haas, )
Vitalii Tymchyshyn <> wrote:

> the simplest option that will make most people happy would be to
> have a limit (waitable semaphore) on backends actively executing
> the query.

That's very similar to the admission control policy I proposed,
except that I suggested a limit on the number of active database
transactions rather than the number of queries.  The reason is that
you could still get into a lot of lock contention with a query-based
limit -- a query could acquire locks (perhaps by writing rows to the
database) and then be blocked waiting its turn, leading to conflicts
with other transactions.  Such problems would be less common with a
transaction limit, since most common locks don't persist past the
end of the transaction.

-Kevin

В списке pgsql-performance по дате отправления:

Предыдущее
От: Markus Schulz
Дата:
Сообщение: problem with from_collapse_limit and joined views
Следующее
От: Divakar Singh
Дата:
Сообщение: Which gives good performance? separate database vs separate schema