PostgreSQL 12 High Availability Cookbook - Third Edition

Determining connection costs and limits

Excessive database connections are not without risk. The level of risk we incur and what exactly qualifies as excessive are important to determine early. The company and our customers will find it extremely inconvenient if normal database activity exhausts system memory, causes timeouts due to increased context-switching, or overwhelms the kernel with an overly large process table.

To maintain a highly available server, we must know the full impact of every single connection in terms of required memory and CPU resources. Servicing several disparate applications from various external servers is difficult, so we must provide availability while simultaneously avoiding resource exhaustion. If we properly ...