The pt-query-digest is my go-to tool in order to perform slow query analysis, improve query performance and thus overall MySQL performance. In this blog post, I’m going to highlight the…

The post How to filter MySQL slow queries using pt-query-digest first appeared on Change Is Inevitable.

Wondering which databases are trending in 2019? We asked hundreds of developers, engineers, software architects, dev teams, and IT leaders at DeveloperWeek to discover the current NoSQL vs. SQL usage, most popular databases, important metrics to track, and their most time-consuming database management tasks. Get the latest insights on MySQL, MongoDB, PostgreSQL, Redis, and many others to see which database management systems are most favored this year.

SQL vs. NoSQL

As any database administrator knows, the first question you have to ask yourself is whether to use a SQL or NoSQL database for your application. …

In this blog post,  I’ll look at how to catch slow and frequent queries with ProxySQL.

More and more people are using ProxySQL because it is a great tool and it can help DBAs a lot. But many people do not realize that it is more powerful than it looks. It has many features and possibilities. I am going to show you one of my favorite “tricks” / use cases.

There are plenty of blog posts explaining how ProxySQL works. I am not going to that again. Instead, let’s jump straight to the point. There is a table in ProxySQL called “stats.stats_mysql_query_digest”. It is one of my favorite tables because it basically records all the queries that were running against ProxySQL. Without collecting any queries on the MySQL server, I can find …

In this blog, I will provide answers to the Q & A for the Troubleshooting Slow Queries webinar.

First, I want to thank you for attending the April 28 webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer during the webinar, with responses:

Q: I’ve heard that is a bad idea to use

select *

; what do you recommend?

A: When I used

SELECT *

 in my slides, I wanted to underline the idea that sometimes you need to select all columns from …

When a new version of MySQL is about to be released we read a lot of blog posts about the performance and scalability improvements. That’s good but sometimes we miss some small features that can help us a lot in our day-to-day tasks. One good example is the blog post that Aurimas wrote about a new small feature in MySQL 5.6 that I didn’t know about until I read it: the Automatic InnoDB transaction log file size change. How cool is that?

I plan to write a series of blog posts that will show some of those small new features in MySQL 5.7 that are going to be really useful. I’m going to start with EXPLAIN FOR CONNECTION.

This feature allows us to run an EXPLAIN for an already running statement. Let’s say that you find a query …

You might have encountered situations where you had to kill some specific select queries that were running for long periods and choking the database. This post will go into more detail with an example of report query offloading.

Report query (select) offloading to a slave server is a common practice to reduce the workload of the master DB server. The long running selects will be executed in the slave for report generation. I have observed in many cases where the slave used to get delayed or the slave DB encounters a slowdown due to some heavy long-running orphaned selects from some wrong reports.

There are two main ways to kill queries in MySQL: 1. use custom scripts that match on a regular expression, or 2. use a tool written and supported by Percona that is designed to kill queries based on matching conditions. Below is one script that will help you to kill those queries. The script will take the process list from MySQL and …

Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common reason is that queries are taking more time on slave then master. How to check and log those long-running queries?  From MySQL 5.1, log-slow-slave-statements variable was introduced, which you can enable on slave and log slow queries. But what if you want to log slow queries on slave in earlier versions like MySQL 5.0?  There is a good solution/workaround: pt-query-digest. How? …

I am publishing my MySQL related bookmark collection http://www.mysqlpreacher.com/bookmarks/.

Feel free to send me links you think might be good to add in order to help others.

Remember, SHARING IS CARING!!! …. we get so much for free, why shouldn’t we give some back?

Cheers,
Darren