Remove all queries to get table schema

[kenjis]

Some ORMs exec queries to get table schema like below:

SHOW FULL COLUMNS FROM `post`

We should configure all ORMs not to exec the queries like this.

[cebe]

Yii needs them to work but can cache them. So the first request will still execute these. Speed then differs dependend on the cache used so it gets even harder to get a fair benchmark.

[samdark]

There could be warmup query before testing.