Re: Database performs massive reads when I'm doing writes.
| От | bricklen |
|---|---|
| Тема | Re: Database performs massive reads when I'm doing writes. |
| Дата | |
| Msg-id | CAGrpgQ_nJftTLEb+7zXtXD46wotHO5AZLv9OJi+yQgx1UM6XUg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Database performs massive reads when I'm doing writes. (Ray Cote <rgacote@appropriatesolutions.com>) |
| Ответы |
Re: Database performs massive reads when I'm doing
writes.
|
| Список | pgsql-general |
On Thu, Jun 6, 2013 at 9:53 AM, Ray Cote <rgacote@appropriatesolutions.com> wrote:
Starting a few days ago we started to see a strange behavior where writing to the database causes massive read operations.
For example, I have a table that needs to be updated every night (about 20,000 rows).
Using Django ORM, we update them one item at a time.
Usually the overall process takes a few minutes; it is now taking hours (like over 15 hours).
Running atop, we're seeing Read Disk values in the range of 147.2M/10s and Write Disk values in the range of 16K/10s.
Together, the Disk throughput is in the high 90% and frequently hits 100%.
When I'm not writing to the database, it becomes quiet without any disk activity.
This is a 256 MByte system and atop shows we're not swapping
Is autovacuum set to 'on'?
Possibly there is bloat in your table and indexes; what happens to the system after you issue a manual "VACUUM ANALYZE VERBOSE"? If that helps, you might need to make your autovacuum settings more aggressive.
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