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The slow query log is the trusted old method of recording slow query, so the database administrator can determine which queries are in the most need for optimization. Since MySQL 5.6, it has to some extend been overshadowed by the Performance Schema which has lower overhead and thus allows collecting statistics about all queries. The slow query log has one major advantage though: the data is persisted. In MySQL 8.0.14 which was recently released, there is an improvement for the slow query log: additional statistics about the recorded queries.

The slow query log with log_slow_extra enabled.

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As you may have noticed by now, we are continuously improving and enhancing the experience of managing a MySQL server. Furthermore, we have also released tools, such as MySQL shell, that make advanced and distributed setups like creating, deploying, and running clusters of InnoDB instances, seamless to the end user.…

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We are less than 48h before the more and more popular pre-FOSDEM MySQL Day !

Unfortunately one of our speaker won’t be able to deliver his talk. Indeed, Giuseppe had ton cancel is talk on containers (Automating MySQL operations with containers) but he will be present during the day and during the Community Dinner, so if you have questions, I’m sure he will gladly answer them.

So we have replace this great speaker by another great one: Shlomi Noach !

Shlomi will present a very new session: Un-split brain (aka Move Back in Time) MySQL.

Here is the updated …

In a MySQL hosting replication setup, the parameter Seconds_Behind_Master (SBM), as displayed by the SHOW SLAVE STATUS command, is commonly used as an indication of the current replication lag of the slave. In this blog post, we examine how to understand and interpret this value in various situations.

Possible Values of  Seconds Behind Master

The value of SBM, as explained in the  MySQL documentation, depends on the state of the MySQL slave in general, and the states of MySQL slave SQL_THREAD and IO_THREAD in particular. While IO_THREAD connects with the master and reads the updates, SQL_THREAD applies these updates on the slave. Let’s examine the possible values of SBM during different states of the MySQL Slave.

When SBM Value is Null

• SBM is …

The MariaDB Foundation is pleased to announce the availability of MariaDB 5.5.63, the latest stable release in the MariaDB 5.5 series and MariaDB Connector/ODBC 3.1.0, the first release candidate in the MariaDB Connector/ODBC 3.1 series. See the release notes and changelogs for details. Download MariaDB 5.5.63 Release Notes Changelog What is MariaDB 5.5? MariaDB APT […]

The post MariaDB 5.5.63 and MariaDB Connector/ODBC 3.1.0 now available appeared first on MariaDB.org.

I am a Junior DBA at Mydbops. This is my first blog professionally, I would like to brief my encounter with Log-rotate in first few weeks of my work,  Hope it will help other beginners as well. This Blog will cover the following sections.

• Introduction to Log-rotate

• Issues Faced

• Solutions (Fix for the above issues)

• Best practices

  • How to configure the Log-rotate

  • Operation of Log-rotate

  • Files responsible for the Log_rotate utility.

1.0. Introduction to Log-rotate:

• Log-rotate is a utility and …

MySQL 8.0.14 came with Lateral Derived Tables as a new feature.  But what is that and how do you use them?

Let's start what a derived table is.  According to the manual (link below) A derived table is an expression that generates a table within the scope of a query FROM clause.   You are probably used to using a subquery or JSON_TABLE where that query feeds data into another query.

Derived Tables

Derived tables can return a scalar, column, row, or table. But there are limits to their use.
A derived table cannot be a correlated subquery and a derived table cannot contain references to other tables of the same SELECT. And previous to MySQL 8.0.14, a derived table cannot contain outer references.

Okay, so what is an 'outer reference'? The SQL-92 standard …

MySQL 8.0 brought enormous changes and modifications that were pushed by the Oracle MySQL Team. Physical files have been changed. For instance, *.frm, *.TRG, *.TRN, and *.par no longer exist. Tons of new features have been added such as CTE (Common Table Expressions), Window Functions, Invisible Indexes, regexp (or Regular Expression)--the latter has been changed and now provides full Unicode support and is multibyte safe. Data dictionary has also changed. It’s now incorporated with a transactional data dictionary that stores information about database objects. Unlike previous versions, dictionary data was stored in …

FOSDEM is coming up. I do not have a presentation in the MySQL and Friends devroom this year, but it reminded me that I had planned to post a follow-up to my presentation from last year.

As part of the presentation, I showed how you can inspect the content of a histogram using the information schema table column_statistics. For example, the following query will show the content of the histogram for the column l_linenumber in the table lineitem of the dbt3_sf1 database:

SELECT JSON_PRETTY(histogram)
FROM information_schema.column_statistics
WHERE schema_name = …

MySQL InnoDB is more and more popular. The adoption of it is even faster than I expected. Recently, during my travel in Stockholm, Sweden, a customer asked me what was the best practice to backup a cluster.

Since my interlocutor was a customer, the obvious choice is to use MySQL Enterprise Backup (known as MEB). Of course any other physical backup should be also fine.

The customer told me he was using cron to schedule his backup and was only using full backups… That’s perfect. So I told him that there is nothing complicated and that the cron job should something like:

mysqlbackup --with-timestamp --backup-dir /backup  backup

Of course, I do not recommend the use of --user clusteradmin --password=xxxxxin the cronjob but configure your crendentials using …