Обсуждение: autovacuum questions
Hello Gurus, I'm new to PG , running PG 8.3 on Linux and reading trough docs is mentioned that in PG vers 8.3 an AUTO vacuum process has been implemented which will run full vacuum on all user and system tables + analyze and there is NO need fro DBA to schedule a crontab job to run this maintenance jobs . If this is true , here are my questions : Would like to know from your experience is this automated process sufficient and reliable in a warehouse database , can I rely only on this internal process ? How can I see when the job has been run or completed by PG ? I have configure track_count=true, what values should I go for autovacuum_naptime from your experience? Isabella
Hello there,
Yes, the autovacuum is set on by default on the PG 8.3.
The vacuum is not full, to run a full vacuum you need to set a cron job; better to run at the night.
I don't set autovacuum on the production databases, only in the Slony's slave machines and in the developmente machine.
For autovacuum settings you need to set and see if it's ok for you.
to see if the vacuum is running you can use the command "ps axf | grep postgres" on the linux server. Sometimes autovacuum is so fast that you even notice him.
I hope that I helped
Best Regards,
Rafael Domiciano
2008/10/31 Isabella Ghiurea <isabella.ghiurea@nrc-cnrc.gc.ca>
Hello Gurus,
I'm new to PG , running PG 8.3 on Linux and reading trough docs is mentioned that in PG vers 8.3 an AUTO vacuum process has been implemented which will run
full vacuum on all user and system tables + analyze and there is NO need fro DBA to schedule a crontab job to run this maintenance jobs . If this is true , here are my questions :
Would like to know from your experience is this automated process sufficient and reliable in a warehouse database , can I rely only on this internal process ?
How can I see when the job has been run or completed by PG ?
I have configure track_count=true, what values should I go for autovacuum_naptime from your experience?
Isabella
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Rafael Domiciano escribió: > The vacuum is not full, to run a full vacuum you need to set a cron job; > better to run at the night. Doing VACUUM FULL on crontab is rarely a good idea. If you find yourself in a situation where you need VACUUM FULL, then you've not tuned regular vacuum appropriately. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.
On Fri, Oct 31, 2008 at 10:02 AM, Alvaro Herrera <alvherre@commandprompt.com> wrote: > Rafael Domiciano escribió: > >> The vacuum is not full, to run a full vacuum you need to set a cron job; >> better to run at the night. > > Doing VACUUM FULL on crontab is rarely a good idea. If you find > yourself in a situation where you need VACUUM FULL, then you've not > tuned regular vacuum appropriately. There are some use cases where vacuum full is appropriate. But they're rare. And they're usually better off being added to whatever script is doing the thing that causes the database to need vacuum full. Certain batch processing or data loading processes need vacuum full and or reindex when finishing. But the common thought process on vacuum full for most people is "If vacuum is good, vacuum full must be even better!" which is just wrong.