Debug notes on sequelize max-connections issue

sequelize-max-connections-debug-notes.md

Debug Notes for Sequelize + PG max connections issue

The following are commands useful for debugging pool connections in a sequelize + pg setup:

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Connect to local psql shell psql -d <DB_NAME>

Connect to remote psql shell psql --host=<DB_HOST> --port=5432 --username=<DB_USER> --dbname=<DB_NAME>

List max connections SHOW max_connections;

Get pg connections SELECT * FROM pg_stat_activity;

Count pg connections SELECT COUNT(*) from pg_stat_activity;

Display pg connections in a table

SELECT max_conn,used,res_for_super,max_conn-used-res_for_super res_for_normal 
FROM 
  (select count(*) used from pg_stat_activity) t1,
  (select setting::int res_for_super from pg_settings where name=$$superuser_reserved_connections$$) t2,
  (select setting::int max_conn from pg_settings where name=$$max_connections$$) t3;

Reboot sequelize dropdb <DB_NAME>; createdb <DB_NAME>; yarn sequelize db:migrate; yarn sequelize db:seed:all; yarn start-dev