The number of allowed connections to Aiven PostgreSQL instances is limited to try to make sure the database is able to serve all connections. Aiven services'
max_connections setting varies by the plan as follows:
- Hobbyist: 25
- Startup/Business/Premium-4: 100
- Startup/Business/Premium-8: 200
- Startup/Business/Premium-16: 400
- Startup/Business/Premium-32: 800
- Startup/Business/Premium-64 and above: 1000
When there are a lot of clients and/or client threads connecting to the database we recommend using connection pooling to limit the number of actual backend connections. Connection pooling is available in all Aiven PostgreSQL Startup, Business and Premium plans and can be configured in the console. Our blog post http://blog.aiven.io/2016/12/aiven-postgresql-connection-pooling.html describes the feature and how it can be enabled.
If you're unable to use connection pooling for some reason and still need a higher
max_connections value we can manually set it for your database with the understanding that a high connection count can cause your database to run more slowly or even run out of memory causing some outage until it can be restored.