Add multi-db support and lots of comments

pgmon-metrics.cfg

@@ -7,7 +7,8 @@ metric=version:value::SHOW server_version_num
 metric=max_frozen_age:value::SELECT max(age(datfrozenxid)) FROM pg_database
 
 # Per-database metrics
-metric=db_stats:row::SELECT * FROM pg_stat_database WHERE datname = '{datname}'
+metric=db_stats:row::SELECT numbackends, xact_commit, xact_rollback, blks_read, blks_hit, tup_returned, tup_fetched, tup_inserted, tup_updated, tup_deleted, conflicts, temp_files, temp_bytes, deadlocks, blk_read_time, blk_write_time, extract('epoch' from stats_reset) FROM pg_stat_database WHERE datname = '{datname}'
+metric=db_stats:row:160000:SELECT numbackends, xact_commit, xact_rollback, blks_read, blks_hit, tup_returned, tup_fetched, tup_inserted, tup_updated, tup_deleted, conflicts, temp_files, temp_bytes, deadlocks, checksum_failures, blk_read_time, blk_write_time, session_time, active_time, idle_in_transaction_time, sessions, sessions_abandoned, sessions_fatal, sessions_killed, extract('epoch' from stats_reset) FROM pg_stat_database WHERE datname = '{datname}'
 
 # Per-replication metrics
 metric=rep_stats:row::SELECT * FROM pg_stat_database WHERE client_addr || '_' || regexp_replace(application_name, '[ ,]', '_', 'g') = '{repid}'

pgmon.cfg

@@ -36,24 +36,26 @@
 ##
 
 # Log level for stderr logging (or 'off')
-#stderr_log_level=info
+stderr_log_level=debug
 
 # Log level for file logging (od 'off')
-#file_log_level=info
+file_log_level=off
 
 # Log file
 #log_file=pgmon.log
 
 ##
 # DB connection settings
+#
+# Each cluster entry is of the form:
+#   name:address:port:dbname:user:password
+#
+# Any element other than the name can be left empty to use the defaults
 ##
 
-#host=localhost
-host=/var/run/postgresql
-#port=5432
-#user=postgres
-user=zbx_monitor
-#password=None
+#cluster=local:/var/run/postgresql:5432:postgres:zbx_monitor:
+cluster=pg15:localhost:54315:postgres:postgres:
+cluster=pg96:localhost:54396:postgres:postgres:
 
 # Default database to connect to when none is specified for a metric
 #dbname=postgres
@@ -65,4 +67,4 @@ user=zbx_monitor
 # Metrics
 #metrics={}
 
-include=/etc/zabbix/pgmon-metrics.cfg
+include=pgmon-metrics.cfg