https://www.postgresql.org/docs/current/monitoring.html
https://www.postgresql.org/docs/current/monitoring-stats.html
https://www.postgresql.org/docs/current/progress-reporting.html
https://postgrespro.ru/docs/postgresql/current/progress-reporting

pg_stat_activity view

func
    pg_stat_reset
    pg_stat_reset_shared('bgwriter')

views
    pg_stat_database
    pg_stat_all_tables
    pg_stat_all_indexes

    pg_stat_bgwriter
        checkpoints...