MySQL – Fixing: Got fatal error 1236 from master when reading data from binary log: log event entry exceeded max_allowed_packet; Increase max_allowed_packet on master;

If you spend all day every day looking after hundreds of MySQL servers, the chances are that you have encountered this problem. And the chances are that if your servers are configured properly (i.e. you have the same configuration the master and the slaves), the error is almost certainly spurious and doesn’t mean what it […]

MariaDB Performance Tuning and MySQL Performance Tuning

A summary of basics of MariaDB and MySQL performance tuning, along with a few more advanced hints and tips. Beyond these, further tuning becomes very workload specific.

MariaDB and MySQL DROP / TRUNCATE Lock / Stall Bug, Mitigations and Workarounds

When you DROP or TRUNCATE a table or partition in MySQL and you have a large buffer pool, you may noticed a complete server lock-up or stall of multiple seconds. Mitigation and Workarounds.

MariaDB / MySQL Performance Tuning and Optimization: How to Delete Faster on MySQL

DELETE statements can have a disproportionately high impact on performance of a database server. Here we explore techniques for optimizing them.

MariaDB / MySQL Performance Tuning and Optimization: Data Types

Data types matching between the table columns and queries is important – mismatch usually prevents the use of indexes.

MariaDB / MySQL Performance Tuning and Optimization: Sub-SELECTs are Evil

Most DBAs know that sub-selects are typically bad for performance, but this example we encountered in the wild illustrates very well just how bad for performance sub-selects can be.

MariaDB / MySQL Performance Tuning and Optimization: Best Practices for Writing High Performance SQL Queries

In this article we discuss a list of best practices to help you write queries that perform well and avoid writing queries that end up being unoptimizable.

MariaDB / MySQL Performance Tuning and Optimization: Avoiding ORs in Queries

ORs in SQL queries are bad for performance. Here we describe a technique for doing away with the ORs to improve performance while still retaining functional equivalence of the query.

How to Reduce RDS Costs on AWS

AWS, and RDS in particular, can be very expensive. In this article we discuss techniques that can be used to reduce costs without compromising performance.

PMM Missing Disk Stats Fix with Kernels 4.19+

PMM fix for missing disk stats/metrics on newer kernels.