Cesar Arrieta wrote:
im developing an app that saves information included in "pg_stat_activity" view in order to monitor querys. The objective of this app is to gather information about querys that take to long to finish and overload the server.
I hope you're already setting log_min_duration_statement, then analyzing the resulting logs using something like pgFouine. If you have PostgreSQL 8.4 or later, possibly add loading the auto_explain module as well, or collecting the data using pg_stat_statements instead can be useful. Trying to grab this info in real-time from pg_stat_activity instead is a lot of work and won't give you results as good. If you're already doing something like that and are just looking to increase the amount of info you collect by also looking at pg_stat_activity, that can be worthwhile.
Maciek just gave the quickest answer to your main question; I'll just add that reading the source code to the file system_views.sql will show you how pg_stat_activity as well as other interesting built-in views work.
-- Greg Smith 2ndQuadrant US greg@xxxxxxxxxxxxxxx Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us "PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
