Re: PostgreSQL strugling during high load

От: Matthew T. O'Connor
Тема: Re: PostgreSQL strugling during high load
Дата: ,
Msg-id: 428804EA.6080609@zeut.net
(см: обсуждение, исходный текст)
Ответ на: Re: PostgreSQL strugling during high load  ("Mindaugas Riauba")
Ответы: Re: PostgreSQL strugling during high load  ("Thomas F. O'Connell")
Список: pgsql-performance

Скрыть дерево обсуждения

PostgreSQL strugling during high load  ("Mindaugas Riauba", )
 Re: PostgreSQL strugling during high load  ("Steinar H. Gunderson", )
 Re: PostgreSQL strugling during high load  (Tom Lane, )
  Re: PostgreSQL strugling during high load  (Mischa Sandberg, )
 Re: PostgreSQL strugling during high load  ("Mindaugas Riauba", )
  Re: PostgreSQL strugling during high load  (Tom Lane, )
   Re: PostgreSQL strugling during high load  (Donald Courtney, )
  Re: PostgreSQL strugling during high load  (Cosimo Streppone, )
  Re: PostgreSQL strugling during high load  ("Matthew T. O'Connor", )
   Re: PostgreSQL strugling during high load  ("Thomas F. O'Connell", )
 Re: PostgreSQL strugling during high load  ("Mindaugas Riauba", )
  Re: PostgreSQL strugling during high load  ("Steinar H. Gunderson", )
 Re: PostgreSQL strugling during high load  ("Mindaugas Riauba", )
  Re: PostgreSQL strugling during high load  (Tom Lane, )
 Re: PostgreSQL strugling during high load  ("Mindaugas Riauba", )
 Re: PostgreSQL strugling during high load  ("Anjan Dave", )
  Re: PostgreSQL strugling during high load  (Donald Courtney, )
  Re: PostgreSQL strugling during high load  (Vivek Khera, )
  Re: PostgreSQL strugling during high load  (Josh Berkus, )
   Re: PostgreSQL strugling during high load  (Steve Poe, )
 Re: PostgreSQL strugling during high load  ("Anjan Dave", )

Mindaugas Riauba wrote:

>>The "vacuum cost" parameters can be adjusted to make vacuums fired
>>by pg_autovacuum less of a burden.  I haven't got any specific numbers
>>to suggest, but perhaps someone else does.
>>
>>
>
>  It looks like that not only vacuum causes our problems. vacuum_cost
>seems to lower vacuum impact but we are still noticing slow queries "storm".
>We are logging queries that takes >2000ms to process.
>  And there is quiet periods and then suddenly 30+ slow queries appears in
>log within the same second. What else could cause such behaviour? WAL log
>switch? One WAL file seems to last <1 minute.
>
>

How long are these quite periods?  Do the "strom" periods correspond to
pg_autovacuum loops?  I have heard from one person who had LOTS of
databases and tables that caused the pg_autovacuum to create a noticable
load just updateing all its stats.  The solution in that case was to add
a small delay insidet the inner pg_autovacuum loop.


В списке pgsql-performance по дате сообщения:

От: Alvaro Herrera
Дата:
Сообщение: Re: checkpoint segments
От: "Mindaugas Riauba"
Дата:
Сообщение: Re: PostgreSQL strugling during high load