MariaDB/MySQL: Working with MD5 or other hashes
The optimal way to store a MD5 hashes in MariaDB, and how to work with them. Continue reading MariaDB/MySQL: Working with MD5 or other hashes
Category Archives: MySQL
MariaDB: The regexp + LIKE optimisation
MariaDB supports regular expressions, but regexps won’t use indexes. Here’s a workaround that can be used in some cases. Continue reading MariaDB: The regexp + LIKE optimisation
How slow is SELECT * ?
The most widely known query optimisation rule is that developers should always avoid SELECT *. Even when all columns are needed, they should list their names, because more columns could be created in the future. But developers find this really Continue reading How slow is SELECT * ?
Identify useless queries in MariaDB/MySQL
Some queries always fail or never return rows. They should be eliminated to improve database performance. Continue reading Identify useless queries in MariaDB/MySQL
NULL comparisons in MariaDB, PostgreSQL, and SQLite
Comparisons are tricky when NULL values are involved. But some databases offer some special, handy syntax to solve the problem. Continue reading NULL comparisons in MariaDB, PostgreSQL, and SQLite
Finding Duplicate Indexes and Unused Indexes in MariaDB/MySQL
Having many indexes in our databases comes with a cost. It is good to periodically eliminate duplicate and unused indexes. Continue reading Finding Duplicate Indexes and Unused Indexes in MariaDB/MySQL
The risks of replication filters in MariaDB and MySQL
MariaDB/MySQL replication filters may be useful, but they come with some risks that Database Administrators should be aware of. Continue reading The risks of replication filters in MariaDB and MySQL
Can we shrink InnoDB Buffer Pool?
An oversized InnoDB buffer pool will consume too many resources and can be slower than necessary. Let’s see how to check if we can shrink it. Continue reading Can we shrink InnoDB Buffer Pool?
Is InnoDB Buffer Pool big enough?
InnoDB buffer pool is the most important memory area to allocate. It contains the most frequently read data and index entries from InnoDB tables. Let’s see how to check if it is big enough. Continue reading Is InnoDB Buffer Pool big enough?
MariaDB/MySQL IS NULL conditions and indexes
It is quite common to use an equality condition and an IS NULL condition on the same columns. Unfortunately, this could make queries very slow. Continue reading MariaDB/MySQL IS NULL conditions and indexes