Home / server / Questions / 1007453
In Process
Michael Gee
Asked: 2020-03-19 11:55:55 +0800 CST

Can system load on a postgresql replica impact the performance of the source database?

  • 772

I've created a postgresql replica database to mirror the content of my production database and want to be sure that queries against the replica can never impact the production server. How safe am I?

Thanks!

postgresql postgresql-replication

1 Answers

  1. Never say never.

    If you implement synchronous replication, and overload the capacity of the replica, production will need to wait for the secondary. The documentation's HA matrix notes this consideration.

    Even if not using sync replication, in some cases resource consumption may affect performance. Say you replicate to a secondary on the same SAN. WAL replication plus query I/O may saturate the shared storage bandwidth. Primary isn't going to perform well if its storage is maxed out. Prevent this problem with capacity planning, and not sharing storage or compute systems.

    • 0