PostgreSQL 12 High Availability Cookbook - Third Edition

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For an example of this in action, consider a system with 32 GB of RAM, 8 CPU cores, and 8 disk spindles. We used 8 MB for our work_mem setting, so this means we may need up to 40 MB per database connection. 16 GB of RAM can then safely support about 409 connections, assuming memory is our only resource limit.

Otherwise, our 8 CPUs and 8 disks can support up to 24 connections. This is quite a discrepancy! However, 24 is the safer of the two limits to prevent latency. If we find that a certain amount of latency is not overly disruptive, we can increase the connection count, but not higher than 400; otherwise, we risk actually exhausting the available RAM. The ideal value is likely to be between these two extremes and will require ...