You may have noticed that MySQL now supports creating functions (and store procedures) in Javascript using GraalVM.

This new functionality is only available in MySQL Enterprise and MySQL HeatWave.

As a developer, you can also get free access to MySQL Enterprise from Oracle Technology Network (OTN): MySQL Enterprise Download.

I also recommend you look at Øystein’s presentation during the Belgian MySQL Days: [1], [2].

Why use a JS function?

As you may know, UUIDs are increasingly popular and their usage in MySQL is limited to the UUID V1.

I already covered this in the blog post titled …

Maintaining a production dataset at a manageable size can present a considerable challenge during the administration of a MySQL InnoDB Cluster.

Old Days

Back in the day when we only had one main copy of our data (the source), and one read copy (the replica) that we used to look at current and old data from our main system, we used a special trick to remove data without affecting the replica. The trick was to turn off writes to the binary log for our removal commands in the main system. External tools like pt-archiver were also able to use that trick. To stop bypass writing into the binary log, we used the command: SET SQL_LOG_BIN=0.

This mean that on the main production server (replication source), we were purging the data without writing the delete operation into the binary logs:

Current Days

These …