[Milhouse]

Conditional maybe easy, we have the define `HAS_MARIADB`

Great.

Much more difficult is, to do this only for MySQL-backends

Or just disable it regardless of the backend server?

What's odd, though, is that my version of MySQL Server (5.5.21) has query cache enabled and isn't a problem:

Code:

> SHOW VARIABLES LIKE 'version';
'version', '5.5.21'
> SHOW VARIABLES LIKE 'have_query_cache';
'have_query_cache', 'YES'
> SHOW VARIABLES LIKE 'query_cache_size';
'query_cache_size', '67108864'
> SHOW VARIABLES LIKE 'query_cache_type';
'query_cache_type', 'ON'

Maybe there are specific versions of MySQL that cause this problem with the MariaDB connector? It could even just be 5.7.19!

I think we should dig a bit deeper before clobbering the query cache, as we could be disabling it on working MySQL systems unnecessarily.