How to write a script to analyze and vacuum all the tables in the system catalog?Thanks.

On 05/17/2012 11:30 AM, leaf_yxj wrote:

Hi Guys. Please help me about this.

For postgres database, it looks like we need analyze and vacuum all the
tables periodly. I need to write a script which can be executed in crontab.
I don't have any clues about that. I only know the command :
analyze tablename;
vacuum tablename;

Leave off the tablename to do the whole db. But (unless you are on a
really old version of PG) you really shouldn't need to manually vacuum
things as that is the job of the autovacuum process.

There are unusual situations that suggest a manual analyze. It should be
run right after a cluster for instance. But they are limited special cases.

What indicates that you need to vacuum or analyze via cron?

Cheers,
Steve

Hi Steve,

Thanks for your reply.

My Postgresql version is 8.2. I amn't sure we have the autovacuum job running or not? How can I check it ?

Thanks.

Grace

At 2012-05-18 02:53:15,"Steve Crawford" <scrawford@pinpointresearch.com> wrote:

Thanks. Steve

At 2012-05-18 02:54:36,"Steve Crawford [via PostgreSQL]" <ml-node+s1045698n5709066h88@n5.nabble.com> wrote:
On 05/17/2012 11:30 AM, leaf_yxj wrote:

Hi Guys. Please help me about this.

For postgres database, it looks like we need analyze and vacuum all the
tables periodly. I need to write a script which can be executed in crontab.
I don't have any clues about that. I only know the command :
analyze tablename;
vacuum tablename;

Leave off the tablename to do the whole db. But (unless you are on a
really old version of PG) you really shouldn't need to manually vacuum
things as that is the job of the autovacuum process.

There are unusual situations that suggest a manual analyze. It should be
run right after a cluster for instance. But they are limited special cases.

What indicates that you need to vacuum or analyze via cron?

Cheers,
Steve

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On 05/18/2012 06:47 AM, yxj wrote:

Hi Steve,
Thanks for your reply.
My Postgresql version is 8.2. I amn't sure we have the autovacuum job
running or not? How can I check it ?

Unless something is broken it is already running. You can connect to the
db and run "show autovacuum;". It should be on.

Alternately, run "show all;" and scroll down to look at all the
autovacuum settings.

You can also check the running processes. On *nix: if you run "ps -ef |
grep postgres" (assuming typical setups where PostgreSQL is running as
the postgres user) you will see something like:
postgres 14698 1 0 Jan10 ? 01:20:57 /usr/bin/postgres -p 5432 -D
/var/lib/pgsql/data
postgres 14700 14698 0 Jan10 ? 00:07:20 postgres: writer process
postgres 14701 14698 0 Jan10 ? 00:03:09 postgres: wal writer process
postgres 14702 14698 0 Jan10 ? 00:00:21 postgres: autovacuum launcher
process
postgres 14703 14698 0 Jan10 ? 00:51:48 postgres: stats collector process
...

The "autovacuum launcher process" is the one that handles automatically
running vacuum when it is appropriate.

Cheers,
Steve