The schema caching in Yii

Sunday, May 4, 2014

Here we can see the next information:

"If the application is using Active Record, we should turn on the schema caching to save the time of parsing database schema. This can be done by configuring the CDbConnection::schemaCachingDuration property to be a value greater than 0."

I have some questions for it:

1) What gives concrete the schema caching?

2) How does works the schema caching?

3) Where can I see the tests?