Check manual page of postgres_stat_database
Database statistics for PostgreSQL
This check handles the metrics returned from PostgreSQL's statistics
functions pg_stat_database and pg_database_size.
It allows monitoring of disk blocks read, but PostgreSQL seems to not
have a simple "written bytes" or "write IOs" counter, meaning this
information cannot be directly monitored.
Instead, the check allows more fine-grained monitoring of database activity
by tracking what the queries really do.
You can monitor both "read statements" like fetches, as well as
"write statements as update/delete/insert. Finally it allows monitoring of
commits, which PostgreSQL tracks down to the sub-transaction level.
You can then define levels on the per-second amount of the statements.
This check relies on data reported by the agent-side plugin mk_postgres
One item is generated per database.