binlog-row-event-max-size system variable in MySQL 8.0.14

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.

Now, coming back to the server itself, some configuration options that used to be static are now dynamically settable. In addition to that, the SET PERSIST framework is a tool to effortlessly persist the modified values for dynamic system variables. This makes the configuration changes durable across server restarts. All of this adds up to deliver a great user experience to the end user.

Building on that trend, in MySQL 8.0.14, a command line option was turned into a system variable that can be read through a regular session. It can also be changed through SET PERSIST_ONLY, so that on the next server restart, it gets assigned a different value.

The new system variable is binlog-row-event-max-size and this variable tries to set a cap on the maximum size of a row-based binary log event whenver possible. As such the following feature request is now be fixed: BUG#74728. The properties of this variable are:

More details about the work done towards converting the command line option into a system variable can be found here: WL#12385.

So now the user can actually read the value of this variable as well as configure a different value that will be set on the next server restart. Here is a sample:

Thanks for using MySQL. Enjoy!

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About Luis Soares

Luis Soares is the MySQL Replication Director at Oracle. His research interests include replication technologies, dependable systems and high availability. Before joining the MySQL team, he was both a post-graduate student and a researcher at the University of Minho, Portugal, where he designed and implemented group-based replication protocols. Before that, he worked for a Portuguese multi-national company as a system analyst.

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