Tag: query‑planning

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...

Databases are Just Loops - Part 3: Row and Batch execution

Reading Time: 8 min, Date: 5/30/2024

Our database journey makes a brief stop. We need to appreciate an important design decision every database must make: Should I use row or batch execution? Depending on the database - or...

What is Cost in a Query Planner?

Reading Time: 5 min, Date: 12/5/2021

If you ever looked at query plan from a SQL databases - you are likely to have come into something called "cost". You may even have heard that most advanced database use based a...