Thread

1. Monitoring object usage?

   Colin 't Hart <colinthart@gmail.com> — 2010-09-15T11:56:48Z

   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
   

2. Re: Monitoring object usage?

   Jayadevan M <jayadevan.maymala@ibsplc.com> — 2010-09-15T12:28:35Z

   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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3. Re: Monitoring object usage?

   Tomas Vondra <tv@fuzzy.cz> — 2010-09-15T12:37:39Z

   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
   >