intro
Sometimes, performance tuning for databases is a tough nut to crack even for the most experienced DBAs. Walk through the maze with DbVisualizer and master the art of SQL performance tuning today.
Oh, performance. The source of amazement for your customers, excitement for some developers, and a headache like no others when it dives into the ground; even Confucius supposedly once said that behind every well-selling software solution stands a well-performing database.
Well, we’re kidding — Confucius may or may not have said that, but we certainly do. Think about it — you’ve probably ended up reading this blog because you found yourself searching for ways to improve query performance or known methods of SQL performance tuning.
Time to learn more!
What Is SQL Performance Tuning?
On a high level, SQL performance tuning refers to the approaches developers take to improve the performance of their SQL queries. Here’s where things get sticky — “tuning” means different things for different people, but everyone can agree that performance tuning in SQL does something to make queries run faster. That something is done by:
In a nutshell, performance tuning refers to any and all actions designed to keep your database running smoothly. The result of a database running smoothly include more customers for businesses, more work for you, and more happiness on the face of your boss. And, just so you know, everything works the other way around, too.
When to Turn to SQL Performance Tuning?
Turn to performance tuning once:
Right, you got it — you need SQL performance tuning once you need to build a performant database architecture or check up on one. Maybe you’re destroying one and getting ready for a workshop or two — who knows… Regardless, the icing on the cake is the same — database performance tuning is of interest. Ways to tune your precious data store, however, differ from database to database.
How to Tune Databases?
The ways to tune database management systems differ from database to database, but there are parts of general advice applicable to almost anything. When it comes to tuning your database, SQL performance tuning will encompass queries, database architecture, and things related to them.
Seemingly few things to care about, right? Not so fast — a lot is connected to them:
| Object | Connection |
|---|---|
| Search form (a form used to search for something on an app or a website) | Search queries modify SQL queries once a user elects to search for something. The architecture of your database is always a limiting factor for the speed of your SQL queries. |
| Contact form | The contact form on your website or application will ask the user for information including, but not limited to his email address, name, and details of his inquiry. These details will, presumably, be forwarded to a database and then acted on by you or the people around you. |
| A dropdown in a select menu | To obtain the data displayed in the dropdown menu, your database has to select a set of data based on some parameters and only then can the user be provided with the dropdown of available options. |
| A header (navigation) menu | Sometimes, navigation bars in a website take and display information from a table in a database — that’s the case in many content management systems like WordPress, MyBB, vBulletin, IPBoard, and the like. |
| Objects derived from a database and displayed on your website or application | Take a website like Amazon — it displays products, their images, and other information related to them. This information almost certainly comes from a database management system. The data the DBMS displays are selected based on user behavior and input and the same can be said about most other shopping-related websites. |
Got the point? Almost everything related to your website or application undoubtedly comes from a database — that database needs to be cared for. To care for your database, start from the basics and work your way up with these SQL performance tuning tips:
| SQL Performance Tuning Tip | Explanation |
|---|---|
| Queries are tasks composed of other tasks. | SQL queries are tasks composed of other tasks. To improve their performance, optimize the performance of those tasks or get rid of them altogether. |
| Default parameters are often the reason behind slow query performance. | You would be surprised how many developers run their applications without a slightest modification to their database parameters — many do so unintentionally as they’re simply unaware of the gems packed by their database, while some may elect to do so with intent knowing that their use case doesn’t allow them such a luxury (e.g. when using shared hosting, low-performance VPS, etc.) Regardless, always be mindful that every database management system allows you to optimize its parameters through configuration files. |
| To make query performance faster, select as little data as possible. | This piece of advice is gold when dealing with reads: the less data you select, the less data your database has to examine, and your queries will be faster as a result. |
| Optimize within reason, and make sure the optimizations are used by your database. | If you elect to modify the parameters used within your database, make sure you fully understand what they do by digging into the documentation and optimize carefully. It’s a good idea to launch the application you have in a live environment as a demo first, then check if the parameters aren’t overwhelming your server. This may not always be possible, so weigh the upsides and downsides and choose carefully. |
| Documentation can be wrong (sometimes.) | I’ve heard of instances where documentation of MySQL advised developers to take one path, while the engineering team advised them to take another due to reasons related to the internal functionality of the DBMS. The documentation was wrong. That’s not always the case (most of the time you’re fine), so check your sources carefully and make wise decisions. |
| The interpretation of certain values in a database management system can vary wildly depending on your use case. | Ever heard of NULL values? I’m sure you did. Now try inserting a NULL value into a partitioned table in MySQL and tell me what happens: you will notice that the NULL value will reside in the lowest possible partition. That’s only one of such mechanisms — databases have quirks you need to be aware of, and experience will walk you through most of them within time. |
These tips are applicable to almost any database management system — specific database management systems will necessitate specific tips applicable to them and your use case.
So, as always, refer to the documentation of your database management system in question or, if you find yourself using SQL clients or related tooling, to their blogs. TheTable by DbVisualizer is a great place to start as we blog about database performance, availability, and security and other topics.
Another good place to flex your SQL performance tuning muscles is by reading books on database management systems — Hacking MySQL: Breaking, Optimizing, and Securing MySQL for Your Use Case will not only let you understand how best to optimize MySQL for your specific use case, but also walk you through the pitfalls that make your database necessitate optimization in the first place (in other words, tell you how exactly you broke your database to the point you need optimizations), and help you secure your data.
There is much more that can be said about performance tuning in SQL — but as always, the greatest things come from experience.
Experience the bright world of databases: and know that help is always within reach of your hand once you necessitate it: DbVisualizer will help you understand not only if the performance tips you applied are working, but also help you format your SQL queries and help you work with 50+ data sources. Try DbVisualizer today for free for 21 days, and we’ll see you in the next one.
Summary
The term “SQL performance tuning” is an entrance to a scary realm for many. When we dig deeper into it, though, that term is not as scary as it seems at all — a couple of general tips will put you on the right track. We hope that this blog helped you see it, or if you’re on it, helped you find a way forward, and that you will come back to read upcoming blogs as well.
FAQ
What is SQL performance tuning?
SQL performance tuning refers to the practices that help SQL queries within databases run as fast as possible under any circumstances or use cases. Many performance tips are applicable not only to your specific database management system, but also to databases in general — mental models provide great pathways into understanding what and why you’re working with.
How to build a high-performing database?
To build a high-performing database, start from the bottom. Identify your use case, objects that interact with your database, and start optimizing bearing the basics in mind.
Where can I learn more about performance tuning in SQL?
To learn more about SQL performance tuning, follow database blogs like TheTable, read books like Hacking MySQL, and attend industry conferences and gatherings like Database Frontiers to network with like-minded people, build connections, and share expertise.
