PostgreSQL High Performance Cookbook

Performing a seek rate test

In this recipe, we will be discussing how to benchmark the disk seek rate speed using open source tools.

Getting ready

A file can be read from the disk in two ways: sequentially and at random. Reading a file in sequential order requires less effort than reading a file in random order. In PostgreSQL and other database systems, a file needs to be scanned in random order as per the index scans. During the index scans, as per the index lookups, the relation file needs to fetch the data randomly, by moving its file pointer backward and forward, which needs an additional mechanical overhead in spinning the disk in the normal HDD. In SSD, this overhead is lower as it uses the flash memory. This is one of the reasons why we ...