Re: 10K vs 15k rpm for analytics

От: Kevin Grittner
Тема: Re: 10K vs 15k rpm for analytics
Дата: ,
Msg-id: 4B960BD4020000250002FA5D@gw.wicourts.gov
(см: обсуждение, исходный текст)
Ответ на: Re: 10K vs 15k rpm for analytics  ("Pierre C")
Список: pgsql-performance

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10K vs 15k rpm for analytics  (Francisco Reyes, )
 Re: 10K vs 15k rpm for analytics  (Yeb Havinga, )
  Re: 10K vs 15k rpm for analytics  (Greg Smith, )
   Re: 10K vs 15k rpm for analytics  (Yeb Havinga, )
    Re: 10K vs 15k rpm for analytics  ("Pierre C", )
  Re: 10K vs 15k rpm for analytics  (Dave Crooke, )
  Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
   Re: 10K vs 15k rpm for analytics  (Yeb Havinga, )
 Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
 Re: 10K vs 15k rpm for analytics  (, )
  Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
   Re: 10K vs 15k rpm for analytics  (Greg Smith, )
    Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
     Re: 10K vs 15k rpm for analytics  (Greg Smith, )
      Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
       Re: 10K vs 15k rpm for analytics  (Greg Smith, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
  Re: 10K vs 15k rpm for analytics  (Greg Smith, )
  Re: 10K vs 15k rpm for analytics  (Yeb Havinga, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
  Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
   Re: 10K vs 15k rpm for analytics  (, )
    Re: 10K vs 15k rpm for analytics  (Scott Carey, )
     Re: 10K vs 15k rpm for analytics  (Greg Smith, )
      Re: 10K vs 15k rpm for analytics  ("Pierre C", )
       Re: 10K vs 15k rpm for analytics  ("Ing. Marcos Ortiz Valmaseda", )
       Re: 10K vs 15k rpm for analytics  (, )
       Re: 10K vs 15k rpm for analytics  ("Kevin Grittner", )
       Re: 10K vs 15k rpm for analytics  (Michael Stone, )
      Re: 10K vs 15k rpm for analytics  (Scott Carey, )
       Re: 10K vs 15k rpm for analytics  (Scott Carey, )
       Re: 10K vs 15k rpm for analytics  (Greg Smith, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
  Re: 10K vs 15k rpm for analytics  (Scott Carey, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
 Re: 10K vs 15k rpm for analytics  (Greg Smith, )
  Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
  Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )
  Re: 10K vs 15k rpm for analytics  (Greg Smith, )
 Re: 10K vs 15k rpm for analytics  (Francisco Reyes, )
  Re: 10K vs 15k rpm for analytics  (Yeb Havinga, )
 Re: 10K vs 15k rpm for analytics  (Scott Marlowe, )

"Pierre C" <> wrote:
> Greg Smith <> wrote:

>> I'm curious what you feel those weaknesses are.
>
> Handling lots of small files, especially deleting them, is really
> slow on XFS.
> Databases don't care about that.

I know of at least one exception to that -- when we upgraded and got
a newer version of the kernel where XFS has write barriers on by
default, some database transactions which were creating and dropping
temporary tables in a loop became orders of magnitude slower.  Now,
that was a silly approach to getting the data that was needed and I
helped them rework the transactions, but something which had worked
acceptably suddenly didn't anymore.

Since we have a BBU hardware RAID controller, we can turn off write
barriers safely, at least according to this page:

http://xfs.org/index.php/XFS_FAQ#Q._Should_barriers_be_enabled_with_storage_which_has_a_persistent_write_cache.3F

This reduces the penalty for creating and deleting lots of small
files.

-Kevin


В списке pgsql-performance по дате сообщения:

От: "Kevin Grittner"
Дата:
Сообщение: Re: Deleting Large Objects
От: Scott Carey
Дата:
Сообщение: Re: 10K vs 15k rpm for analytics