Database Management systems have evolved over the years, yet it is crucial to stick to the basics to optimize their performance. From a developer’s perspective, one of the most critical components for an efficient, database-driven application is an SQL Query.
One ill-written SQL Query can not only slow down the entire database but also affect other components of the application. Good observation and statistical analysis are critical, but, MySQL comes loaded with specific tools and techniques to optimize SQL Queries and improve the overall time of the database. Let’s have a look at some of these MySQL query techniques.
Benchmarking
Assumptions are limited to certain conditions. Hence, numbers are required to support your results and give you clarity on the efficiency. Benchmarking points out the issues in the queries such as bottlenecks, and bad queries.
With the help of certain profiling tools such as SuperSmack and SysBench, it is possible to simulate high-stress situations and find faults in the database. This process creates the pathway to solution through simulation.
Profiling a MySQL Query
Post the simulation of high-stress situations through the benchmarking process, it is important to point out the cracks in the database. This can be done using profiling. The primary function of the profiling process is to point to the bottlenecks present in the CPU, memory, disk I/O, network, and/or any other component.
After the identification of slow queries, use of internal MySQL tools like EXPLAIN, STATUS, and SHOW will give you information regarding the use of resources and their side effects. This process helps identify the slow queries.
Schema Designing
This step is a pre-prep for query execution. A schema design needs to be completed before any query can even be written. When creating a schema, keeping in mind the details such as memory requirements and the type of data to be entered can help optimize MySQL query execution.
This process of normalizing a database, unlike a popular opinion of creating a complex schema, leads to minimizing redundancy of the data, hence speeding up the query. To make the most of your MySQL query, normalizing is essential. Moreover, if required, de-normalization can be processed later.
Indexing
A query is only as good as the choice of indices, so selecting the index is very important. An index, usually a B-tree, speeds up the process of a query. If a query is executed without any index, then the DBMS must scan every row of the table and compare it with the given condition. However, MySQL query can be optimized, by merely using an index.
During the process, one needs to maintain a balance. Not only do indexes take up memory space, but also affect the write performance as they have to be updated after every ‘write’ operation. Profiling helps to understand this balance, which will vary from situation to situation.
Partitioning the tables
For any database, it is essential to identify and differentiate between frequently used data and otherwise. A common example could be a blog where data such as ‘title of the topic’ might be used more regularly than other content. Now, based on this differentiation, if partitioning is performed the infrequently used data will take up less memory and help optimize the query executed.
When the data is kept in separate tables, the caching process is simplified. The reason being that MySQL will no longer have to change cache for the unaffected data.
MySQL queries might seem extremely simple or extremely complex, but some simple tips mentioned above can change the entire perspective and give a more efficient MySQL database.
I have almost 2 decades of experience in MySQL database tuning and performance. Get in touch with me and I can show you how you can improve your application performance.
Eric Vanier
Database PerformanceTechnical Blog Writer - I love Data
