Re: count * performance issue

От: Bruce Momjian
Тема: Re: count * performance issue
Дата: ,
Msg-id: 200803061533.m26FXPe19222@momjian.us
(см: обсуждение, исходный текст)
Ответ на: Re: count * performance issue  (Craig James)
Список: pgsql-performance

Скрыть дерево обсуждения

count * performance issue  ("sathiya psql", )
 Re: count * performance issue  (Chris, )
 Re: count * performance issue  ("A. Kretschmer", )
  Re: count * performance issue  ("Shoaib Mir", )
   Re: count * performance issue  ("sathiya psql", )
    Re: count * performance issue  ("Shoaib Mir", )
     Re: count * performance issue  ("sathiya psql", )
      Re: count * performance issue  ("Shoaib Mir", )
   Re: count * performance issue  (Mark Mielke, )
    Re: count * performance issue  ("A. Kretschmer", )
     Re: count * performance issue  ("sathiya psql", )
      Re: count * performance issue  ("A. Kretschmer", )
      Re: count * performance issue  (Dave Cramer, )
 Fwd: count * performance issue  ("sathiya psql", )
 Re: count * performance issue  ("A. Kretschmer", )
  Re: count * performance issue  ("sathiya psql", )
   Re: count * performance issue  ("A. Kretschmer", )
   Re: count * performance issue  (Greg Smith, )
  Re: count * performance issue  (Mark Mielke, )
 Re: count * performance issue  (Dave Cramer, )
  Re: count * performance issue  ("sathiya psql", )
   Re: count * performance issue  ("Harald Armin Massa", )
   Re: count * performance issue  ("A. Kretschmer", )
   Re: count * performance issue  (Alvaro Herrera, )
   Re: count * performance issue  (Greg Smith, )
    Re: count * performance issue  (Craig James, )
     Re: count * performance issue  (Bruce Momjian, )
     Re: count * performance issue  ("Steinar H. Gunderson", )
      Re: count * performance issue  (Greg Smith, )
       Re: count * performance issue  ("Dave Page", )
     Re: count * performance issue  (Bill Moran, )
     Re: count * performance issue  ("Mark Lewis", )
     Re: count * performance issue  ("D'Arcy J.M. Cain", )
     Re: count * performance issue  (Tom Lane, )
      Re: count * performance issue  (Craig James, )
       Re: count * performance issue  (paul rivers, )
       Re: count * performance issue  (Mark Kirkwood, )
       Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
        Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )
        Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Joshua D. Drake", )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
          Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Greg Smith, )
           Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Joshua D. Drake", )
            Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Greg Smith, )
             Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Michael Stone, )
        Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Justin Graf", )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Doug Knight, )
          Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Will Weaver, )
          Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Justin Graf", )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
      Re: count * performance issue  (Josh Berkus, )
       Re: count * performance issue  (Tom Lane, )
        Re: count * performance issue  (Greg Smith, )
         Re: count * performance issue  (Tom Lane, )
        Re: count * performance issue  (Gregory Stark, )
         Re: count * performance issue  ("Joe Mirabal", )
          Re: count * performance issue  (Bill Moran, )
           Re: count * performance issue  (Greg Smith, )
          Re: count * performance issue  ("Scott Marlowe", )
          Re: count * performance issue  (Greg Smith, )
           Re: count * performance issue  ("Robins Tharakan", )
            Re: count * performance issue  (Mark Mielke, )
            Re: count * performance issue  ("Joshua D. Drake", )
            Re: count * performance issue  ("Scott Marlowe", )
             Re: count * performance issue  (Albert Cervera Areny, )
            Re: count * performance issue  (Bill Moran, )
             Re: count * performance issue  (Matthew, )
              Re: count * performance issue  (Tino Wildenhain, )
               Re: count * performance issue  (Matthew, )
                Re: count * performance issue  ("Heikki Linnakangas", )
                Re: count * performance issue  (Andrew Sullivan, )
       Re: count * performance issue  (Mark Mielke, )
        Re: count * performance issue  (paul rivers, )
     Re: count * performance issue  (Mark Kirkwood, )
     Re: count * performance issue  (Arjen van der Meijden, )
  Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )
   Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )
   Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Jesper Krogh, )
   Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
    Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Greg Smith, )
     Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
      Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
       Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Dave Cramer, )
        Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Dave Cramer, )
          Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )
          Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
           Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Tino Wildenhain, )
           Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Andrej Ricnik-Bay", )
           Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig Ringer, )
            Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
         Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Michael Stone, )
  Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Dave Cramer, )
   Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
    Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Craig James, )
     Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Justin, )
      Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Enrico Sirola, )
       Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )
      Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (James Mansion, )
 Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("justin", )
  Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )
   Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  (Jesper Krogh, )
 Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("justin", )
  Re: Benchmark: Dell/Perc 6, 8 disk RAID 10  ("Scott Marlowe", )

Craig James wrote:
> This is a real problem.  Countless people (including me) have
> spent significant effort rewriting applications because of this
> performance flaw in Postgres.  Over and over, the response is,
> "You don't really need to do that ... change your application."
> Well, sure, it's always possible to change the application, but
> that misses the point.  To most of us users, count() seems like
> it should be a trivial operation.  On other relational database
> systems, it is a trivial operation.
>
> This is really a significant flaw on an otherwise excellent
> relational database system.

Have you read the TODO items related to this?

--
  Bruce Momjian  <>        http://momjian.us
  EnterpriseDB                             http://postgres.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +


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