September 17, 2014

Webinar: Avoiding common traps when designing a MySQL application

On January 16th at 10 AM Pacific/1 PM Eastern, I will give a webinar about the main traps that are awaiting you when designing and building a stable and high-performance MySQL application. I will discuss a broad range of topics, from hardware and backups to instrumentation and indexing. I often see during my consulting practice […]

How to find MySQL queries worth optimizing ?

One question I often get is how one can find out queries which should be optimized. By looking at pt-query-digest report it is easy to find slow queries or queries which cause the large portion of the load on the system but how do we know whenever there is any possibility to make this query […]

How to diagnose errors in the MySQL error log

I frequently see questions about how to understand the nature of errors in MySQL’s error log. Now, there is a lot of complexity to this — the flowchart would be quite large, as with any nontrivial piece of software. But there is one particular class of errors that is relatively easy to diagnose, if you […]

Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

This is the second blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is aimed at the optimizer enhancement Multi Range Read (MRR). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take a look at […]

Troubleshooting MySQL Upgrade Performance Regressions

So lets say you upgraded from MySQL 5.1 to Percona Server 5.5 and instead of expected performance improvement you see your performance being worse. What should you do ? First if you followed MySQL upgrade best practices such as testing your workload with pt-upgrade the chances of this happening are rather slim. But lets assume […]

MySQL Life Cycle. Your Feedback is needed.

When I started with MySQL 3.22 I would start running MySQL from early beta (if not alpha) and update MySQL the same date as release would hit the web. Since that time I matured and so did MySQL ecosystem. MySQL is powering a lot more demanding and business critical applications now than 12 years ago […]

When EXPLAIN estimates can go wrong!

I have been working with a few customer cases and one interesting case popped up. The customer was facing a peculiar problem where the rows column in the EXPLAIN output of the query was totally off. The actual number of rows was 18 times more than the number of rows reported by MySQL in the […]

What’s required to tune MySQL?

I got a serendipitous call (thanks!) yesterday asking what would be needed to tune[1] a database for better performance. It is a question that I hear often, but I never thought about answering it in public. Here’s a consolidated version of what I explained during our conversation.

How Percona diagnoses MySQL server stalls

We receive many requests for help with server stalls. They come under various names: lockup, freeze, sudden slowdown. When something happens only once or twice a day, it can be difficult to catch it in action. Unfortunately, this often leads to trial-and-error approaches, which can drag on for days (or even months), and cause a […]

An argument for not using mysqldump

I have a 5G mysqldump which takes 30 minutes to restore from backup.  That means that when the database reaches 50G, it should take 30×10=5 hours to restore.  Right?  Wrong.