PostgreSQL 10 High Performance - Third Edition

Database-wide totals

Many of the same pieces of data available at the table level are also summarized per database. You can get the following information out of pg_stat_database and use it in similar ways to pg_stat_user_tables and pg_statio_user_tables:

    SELECT datname,blks_read,blks_hit,tup_returned,tup_fetched,tup_inserted ,tup_updated,tup_deleted FROM pg_stat_database;
  

In addition, there are some useful transaction commit statistics available, as well as a count of the total active client backend connections active for each database:

    SELECT datname,numbackends,xact_commit,xact_rollback from pg_stat_database;