In this blog post, I’ll examine when looking at raw MySQL query logs can be more useful than working with tools that only have summary data.

In my previous blog post, I wrote about analyzing MySQL Slow Query Logs with ClickHouse and ClickTail. One of the follow-up questions I got is when do you want to do that compared to just using tools like Percona Monitoring and Management or VividCortex, which provide a beautiful interface for detailed analyses (rather than spartan SQL interface).    

MySQL Logs

Oracle will be hosting a MySQL Storage Engine Vendor Meeting next week. I have invited all the usual folks who participate but with the changes in MySQL 8, I may not know if you and or your company is contemplating a new storage engine or are planned to use MySQL 8. Last year we had about ten attendees discussing various topics and I would like to have you too there is you are interested. Please contact me by close of business this Friday if you are interested and will be in the Santa Clara area.

Narrowing down which queries to optimize is a step in database administration that is often skipped - however it shouldn't be!  

Why is selecting the right queries to optimize so important? There are several reasons. 

Penny-Wise, Pound-Foolish  Look at the forest, not just the trees, and optimize globally, not locally. If you’re optimizing a query that never causes a user-visible problem, doesn’t impact other queries, and doesn’t significantly load servers, you might be “optimizing” things that don’t matter, spending more money than you save. Your time has value, too! Keep in mind, too, that optimizing a query that generates only 1% of the database’s overall load will not be a significant benefit to the bottom line.   Whack-A-Mole Queries It’s very common to  find a slow query in a log file, try re-executing it and  then find that it is fast. …

We just love to make our users’ life a bit easier. This time, we are excited to treat you with a brand new addition to our dbForge for MySQL product line, – dbForge Documenter for MySQL. The tool automatically generates documentation for multiple MySQL and MariaDB databases in the HTML, PDF, and MARKDOWN file formats […]

In this blog post, we’ll look at using hints to analyze queries.

There are a lot of things that you can do wrong when writing a query, which means that there a lot of things that you can do to make it better. From my personal experience there are two things you should review first:

1. The table join order
2. Which index is being used

Why only those two? Because many other alternatives that are more expensive, and at the end query optimization is a cost-effectiveness analysis. This is why we must start with the simplest fixes. We can control this with the hints “straight_join” and “force index”. These allow us to execute the query with the plan that we would like to test.

Join Order

In a query where we use multiple tables or …

The Madrid MySQL Users Group has been a bit quiet recently so we thought it would be good to have a meeting again. The next meeting will take place next on Wednesday, 25th April and will cover Galera Cluster (Presentation by Emanuele Mottola).  We will also talk about MySQL 8.0 and any latest updates that … Continue reading MMUG19: Multi-instances with Galera Cluster and MySQL 8.0 on 25th April in Madrid

The post MMUG19: Multi-instances with Galera Cluster and MySQL 8.0 on 25th April in Madrid first appeared on Simon J Mudd's Blog.

Please join Percona’s Architect, Tibi Köröcz as he presents Percona XtraDB Cluster 5.7 Tutorial on Wednesday, April 18, 2018, at 7:00 am PDT (UTC-7) / 10:00 am EDT (UTC-4).

Never used Percona XtraDB Cluster before? Come join this 45-minute tutorial where we will introduce you to the concepts of a fully functional Percona XtraDB Cluster.

In this tutorial, we will show you how you can install Percona XtraDB Cluster with ProxySQL, and monitor it with Percona …

Although only available as a Release Candidate, MySQL 8 is already proving itself to be a huge leap forward in many regards. Error logging is no exception. The MySQL development team just announced that they have redesigned the error logging subsystem to use a new component architecture.

The redesign will allow the filtering of log events, as well as the routing of error log output to multiple destinations, via the enabling of multiple sink components.  This will make it possible to send error log events to third-party systems for additional formatting and analysis.

In today’s blog, we’ll explore how to employ MySQL 8’s component-based error logging to achieve a variety of logging configurations. Note that all this is specific for MySQL 8 and is not available in earlier versions and also not in MariaDB. However, MariaDB has an option to write the error log to the system “syslog” on systemd-based Linux variants – …

One of the nice things about MySQL 8.0 is the ability to combine the relational and document models. As a developer, you can choose to work with traditional SQL tables, with schemaless JSON documents, or with both types at the same time.…

Due to continuous development and improvement, Percona Server for MySQL incorporates a number of improvements related to binary log handling and replication. This results in replication specifics, distinguishing it from MySQL Server.

Temporary tables and mixed logging format Summary of the fix:

As soon as some statement involving temporary tables was met when using a mixed binlog format, MySQL switched to row-based logging for all statements until the end of the session (or until all temporary tables used in the session were dropped). This is inconvenient when you have long-lasting connections, including replication-related ones. Percona Server for MySQL fixes the situation by switching between …