Cumulative and live views

There are two types of information you can monitor from the database. The main statistics are stored into counters. These counters start at 0 when you create a new database cluster, increasing with all activity related to that statistic. Counters in this category include pg_stat_database, pg_stat_bgwriter, and all of the other views whose names start with pg_stat.

The exact way that you reset these counters back to 0 again varies quite a bit based on your PostgreSQL version:

• 8.1: pg_stat_reset() resets all statistics. Enablingstats_reset_on_server_start in the postgresql.conf file will reset everything each time the server is started.
• 8.2: pg_stat_reset() resets just block and row level statistics. Enabling stats_reset_on_server_start allows resetting all statistics, including the database and cluster wide ones, each time the server is started.
• 8.3, 8.4: pg_stat_reset() resets all statistics just for the current database. There is no way to reset cluster wide statistics...