Pages tagged: tpch

TPC series - TPC-H Query 6 - Expression Optimisation

Reading Time: 5 min, Date: 10/13/2025

And now, for something completely different. This week on TPC-H query analysis - we are not going to look at join ordering. Today's query does not have any joins. But as we shall see, is to...

TPC series - TPC-H Query 5 - Transitive Closure and Join Order Dependencies

Reading Time: 7 min, Date: 10/8/2025

Welcome back to the TPC-H analysis. If this is your first time, I highly recommend that you visit the previous blogs in the series first. They're here (and I look forward to seeing you in a...

TPC series - TPC-H Query 4 - Semi Join and Uniqueness

Reading Time: 6 min, Date: 9/29/2025

Today we are looking at a Q04 — which on the surface is similar to Q17. Like Q17, Q04 has a correlated subquery that can be de-correlated using a join. But sometimes, a regular INNER JOIN is...

TPC-H series - TPC-H Query 3 - Join Ordering and Heap Sorting

Reading Time: 7 min, Date: 9/10/2025

I want to teach you an important skill that will serve your well as a database specialist. One blog entry is not going to be enough, but here is my goal: When you look at an SQL query in the you...

TPC series - TPC-H Query 2 and 17 - De-correlation

Reading Time: 9 min, Date: 8/29/2025

The great promise databases make to programmers is: "Tell me what you want and I will figure out the fastest way to do it." A database is a computer science engine — it knows and...

Introducing the TPC series - TPC-H Query 1: Column Storage and Local Aggregation

Reading Time: 9 min, Date: 7/14/2025

After the wonderful feedback on the previous blog about Iceberg - it is now time to switch gears. Databases are more than row storage engines. They are algorithm machines, helping that...

TPC series - TPC-H Query 16 - Anti Joins