Cost Based Optimisation is the de-facto standard way to optimise SQL queries in most modern databases. It is the reason why it is really really hard to implement a complex, hand-written algorithm in a 3GL (third generation programming language) such as Java that outperforms a dynamically calculated database execution plan, that has been generated from … Continue reading 10 Cool SQL Optimisations That do not Depend on the Cost Model
Tag: SQL Optimisation
JOIN Elimination: An Essential Optimiser Feature for Advanced SQL Usage
The SQL language has one great advantage over procedural, object oriented, and "ordinary" functional programming languages. The fact that it is truly declarative (i.e. a 4GL / fourth generation programming language) means that a sophisticated optimiser can easily transform one SQL expression into another, equivalent SQL expression, which might be faster to execute. How does … Continue reading JOIN Elimination: An Essential Optimiser Feature for Advanced SQL Usage
Faster SQL Through Occasionally Choosing Natural Keys Over Surrogate Keys
There are many many opinions out there regarding the old surrogate key vs. natural key debate. Most of the times, surrogate keys (e.g. sequence generated IDs) win because they're much easier to design: They're easy to keep consistent across a schema (e.g. every table has an ID column, and that's always the primary key)They're thus … Continue reading Faster SQL Through Occasionally Choosing Natural Keys Over Surrogate Keys