PostgreSQL 10 High Performance - Third Edition

Using buffer cache inspection for sizing feedback

The recent examples give you the basic two things to look for when deciding if your shared_buffers cache is large enough. First, compare what percentage of the relations you believe are important to your application's performance appear to be cached. If this number is low, you may benefit from a larger buffer cache. A helpful secondary look at this information is available if you combine this with hit rates from views such as pg_stat_user_tables which will be covered in Chapter 11, Database Activity and Statistics.

The balance of popular (high usage count) versus transient (low usage count) pages tells you a lot about whether your cache is sized appropriately. If most of your pages have low ...