In our upcoming MariaDB 5.3 release Monty optimized the internal string append code for performance. I tested his patch with a plain MariaDB 5.2 vs. a patched MariaDB 5.2 with sql-bench, which showed an overall performance gain around 3%. The details of the patch Monty describes like this Patch to optimize string append: While examining […]READ MORE
There's innodb_large_prefix as a possible workaround, which is default in 10.2 https://t.co/URwAEaZcN7
The reason is because MariaDB imposes a maximum of 767 bytes for indexes, and 767 / 4 = 191 (rounded down).
The danger of no Primary Key when replicating in RBR (partial protection with MariaDB 10.1) https://t.co/M6mABJdkmn by @jfg956