MariaDB 3.3.3 doesn't seem to support rewriteBatchQueries flag despite documentation statements

There was a recent switch in one of my companies services to use mariadb 3.3.3 which resulted in a significant decrease in performance when batching data. After some research from the development team, the conclusion that was proposed is that although documentation specifies that, in particular, the rewriteBatchQueries flag is supported in this database driver version, the development team could find no mention of the flag ACTUALLY being supported in the driver code.

With this conclusion, we decided to test the same amount of data processing with the mariadb 3.3.3 driver with the flag in place and then switching to mysql 9.2.0 with the flag in place as mysql also deemed the flag supported and we could find evidence of this being the case in their code.

The results were pretty drastic with the mariadb 3.3.3 database driver performance handling ~15 million records in batches of 2500 with the average hovering around ~540 milliseconds and the mysql 9.2.0 database driver performance handling ~15 million records in batches of 2500 with the average hovering around ~250 milliseconds. Due to this increase in performance the timing of actually batching this amount of data with mariadb 3.3.3 was around an hour for ~15 million records and only around 25 minutes for mysql 9.2.0.

Attached are the graph findings.