Обсуждение: Monitoring object usage?

Hi,

I'm trying to get a grip on a new body of code and a Postgres database that I'm working with. In particular I've been tasked with cleaning up the database.

Is there a way in Postgres to enable monitoring on tables and columns to determine what's not actively being used?

This would then form input for a more thorough check into the code base to see what's really not being used.


Thanks & cheers,

Colin

Hi,

> From: "Colin 't Hart" <colinthart@gmail.com>
> To: pgsql-general@postgresql.org
> Date: 15/09/2010 17:37
> Subject: [GENERAL] Monitoring object usage?
> Sent by: pgsql-general-owner@postgresql.org
>
> Hi,
>
> I'm trying to get a grip on a new body of code and a Postgres
> database that I'm working with. In particular I've been tasked with
> cleaning up the database.
>
> Is there a way in Postgres to enable monitoring on tables and
> columns to determine what's not actively being used?
>
> This would then form input for a more thorough check into the code
> base to see what's really not being used.
>

Would the log_statement mentioned here help?
http://www.postgresql.org/docs/current/static/runtime-config-logging.html
I guess it will result in huge log files if it is a 'busy' database.
Probably this has a performance penalty too.

Regards,
Jayadevan





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Well, you can see usage statistics for tables, indexes, functions and
sequences ... but AFAIK it's not possible to do that for columns.

See this
http://www.postgresql.org/docs/8.4/static/runtime-config-statistics.html
and then use pg_stat_ and pg_statio_ catalogs
(http://www.postgresql.org/docs/8.4/static/monitoring-stats.html) to find
objects that were not accessed recently (numbers are 0 or do not change
anymore, etc.).

But be careful as this may backfire quite easily - imagine an index that's
used only in a batch processing the end of month. You could easily decide
it's not necessary and drop it, causing a disaster.

Tomas

> Hi,
>
> I'm trying to get a grip on a new body of code and a Postgres database
> that
> I'm working with. In particular I've been tasked with cleaning up the
> database.
>
> Is there a way in Postgres to enable monitoring on tables and columns to
> determine what's not actively being used?
>
> This would then form input for a more thorough check into the code base to
> see what's really not being used.
>
>
> Thanks & cheers,
>
> Colin
>