Org.postgresql.util.psqlexception: FATAL: sorry, too many clients already

sql

connection-pooling

database-performance

postgresql-optimization

byAnton Shumikhin·Oct 21, 2024

**Diagnose** and **defuse** **PSQLException: FATAL: sorry, too many clients already** by refining your connection management:

1. **Pump up `max_connections`** in **postgresql.conf**:

max_connections = 'new_limit'

//think of it as opening more checkout counters in a busy shop 😉

2. **Dive into a connection pool** like **HikariCP** to effectively manage and reuse connections:
```java
HikariConfig config = new HikariConfig();
config.setMaximumPoolSize('new_pool_size'); //Time for a pool party! Invite only as many guests as we can handle 🎉
HikariDataSource ds = new HikariDataSource(config);

Remember to close the door on your way out: close connections when they're done working using try-with-resources:

 try (Connection conn = ds.getConnection()) {
     // allow the connection to do its thing
 } // connection drops the mic 🎤 and leaves the stage

Double-check that connections always receive their polite goodbyes, and confirm that your pool party rules play nicely with the database's capacity.

Pro-tips for optimizing connections

Before launching a bigger lifeboat, try draining the water from your boat:

Debug lingering connections: Find out if any pesky connections are overstaying their welcome.
Adjust pool party parameters: Check InitialConnections and maxActive values and reconsider the need for an oversized party.
Speed up database interactions: Focus on making your queries and transactions more efficient to free up connections quicker.

Handling connections in containerized PostgreSQL

When dealing with Docker:

Change max_connections for Postgres containers in your docker-compose.yml.
Apply POSTGRES_HOST_AUTH_METHOD=trust with extra caution in dev environments.
Retain your Postgres data using volumes when container settings are modified.

Stay updated with PostgreSQL versions

Stay on top of updates for best performance:

Update to the latest Postgres image in your docker-compose file.
Always check for any compatibility issues after an upgrade, to avoid nasty surprises down the road.

Monitoring: Keeping an eagle eye out on connections

Regularly inspect the number of connections using monitoring tools:

Use pg_stat_activity for real-time connection stats, just like CCTV footage.
Adjust logging parameters to trace long-lasting connections, like tracking loyal customers.

Preparing for the traffic jam: Handling peak loads

Stay prepared for sudden traffic spikes:

Run load testing to simulate high usage scenes.
Set up Failover policies to manage connections during outages or heavy loads.

Connection pool tips: Keep your pool clean and without algae

For optimal use of your pool:

Keep server max_connections higher than total inflatable flamingos in the pool.
Handle exceptions gracefully to ensure no guests are left "floating" around.

Considerations: The 'why's before the 'how's

Before increasing max_connections, think about:

System resources constraints: There's only so much cake to go around at the party.
Performance trade-offs: Having a giant pool party might annoy the neighbors.

explain-codes / Sql / Org.postgresql.util.psqlexception: FATAL: sorry, too many clients already

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