WITH max_age AS ( SELECT 2000000000 as max_old_xid , setting AS autovacuum_freeze_max_age FROM pg_catalog.pg_settings WHERE name = 'autovacuum_freeze_max_age' )
, per_database_stats AS ( SELECT datname , m.max_old_xid::int , m.autovacuum_freeze_max_age::int , age(d.datfrozenxid) AS oldest_current_xid FROM pg_catalog.pg_database d JOIN max_age m ON (true) WHERE d.datallowconn )
SELECT max(oldest_current_xid) AS oldest_current_xid , max(ROUND(100*(oldest_current_xid/max_old_xid::float))) AS percent_towards_wraparound , max(ROUND(100*(oldest_current_xid/autovacuum_freeze_max_age::float))) AS percent_towards_emergency_autovac
FROM per_database_stats
