Basic EXPLAIN
Checking the query plan is an excellent window into the query function. Seeing the query plan steps helps you understand if you can restructure your query or add additional conditions to limit the rows and improve query speed. Comparing the relative costs between different query structures helps you see which plan is more efficient.
Here, you will be examining USA daily air quality data. First, familiarize yourself with running a query that will show the query plan.
This exercise is part of the course
Improving Query Performance in PostgreSQL
Exercise instructions
- Write a query to choose all the columns and rows from the
daily_aqitable. - Add the
EXPLAINcommand to show the query plan.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
___
SELECT *
FROM ___;