How to confirm that the index you added actually improves query performance
Database indexes allow us to speed up queries by providing a method to quickly look up data. However, do we always check that they actually improve performance? In this talk, I explain how and why an automatically added database index did not get used by the queries we expected. Together we will go through SQL produced from Django ORM, index structures and generating database query plans to unravel what was actually going on behind the scenes in our queries.
Within my current role on the performance team, it is my responsibility to investigate sources of and solutions to poor database performance within our company's application. Understanding the how and why of database indexes has been an important part of this, however, my knowledge of database indexes is a relatively recently gained experience. In this talk I aim to share what I have learnt along the way as applied to investigating why an index added in Django was not improving the performance of our database query.
Suzannah has been dabbling in Python since hearing of a notorious C programming subject at university and wanting to get a headstart.
They work as a software engineer at Kraken Technologies.