In the last blog (When PostgreSQL Parameter Tuning is not the Answer), we compared several execution plans for a SQL statement as we made changes to parameters and indexes. Still, there was no mention of what an execution plan is, how one can obtain an execution plan for a query, and how to interpret the result. In this blog, we will take a deep dive into this topic.
Why we need an execution plan?
Most likely, if you ever worked with any relational DBMS, you heard the term execution plan, and moreover, you might have seen some of them. But