PostgreSQLERROR 53300
PostgreSQL: Too Many Connections
PostgreSQL 53300 is raised when the number of client connections reaches the max_connections limit. New connections are refused until existing ones are closed.
Example Query
-- psql: FATAL: sorry, too many clients already
Common Causes
- 1Application not using a connection pool, creating a new connection per request
- 2Leaked connections not closed after use
- 3max_connections set too low for the workload
How to Fix It
Use a connection pooler like PgBouncer or pgpool-II. In application frameworks, configure the connection pool size correctly. Check idle connections: SELECT count(*) FROM pg_stat_activity. Increase max_connections in postgresql.conf if hardware allows (requires restart).
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