Adjusting parameters for good query performance

Writing good queries is the first step to reaching good performance. Without a good query, you will most likely suffer from bad performance. Writing good and intelligent code will therefore give you the greatest edge possible. Once your queries have been optimized from a logical and semantical point of view, good memory settings can provide you with a final nice speedup. In this section, you will learn what more memory can do for you and how PostgreSQL can use it for your benefit. Again, this section assumes that we are using single-core queries to make the plans more readable. To ensure that there is always just one core at work, use the following command:

test=# SET max_parallel_workers_per_gather TO 0;
SET

Here is a simple example demonstrating what memory parameters can do for you:

test=# CREATE TABLE t_test (id serial, name text...