Optimization

[adixon]

As per https://mariadb.com/kb/en/configuring-mariadb-for-optimal-performance/

1. set innodb_buffer_pool_size to 80% of the amount of memory that should be used, defaults to 134217728 (128MB). Since 10.2.2, this can be set dynamically.
2. set key_buffer_size to a very low value, like 64K (since not using myisam).
3. set host_cache_size from default 128 to a low number (only ever connecting from 2 hosts).