Caching of schema from JDBC connection

["Kirz, Thomas" <th...@uni-passau.de>]

Hi,

I am using Calcite parse retrieve the result and parameter types of PreparedStatements.
To do this, I create a JDBCSchema connected to a (SQLite or Postgres) data source (once) and then parse and convert to RelNode each statement string.
I wanted to find out if Calcite stores/caches the schema locally after converting the first SQL statement, so it does not have to connect to the database when converting subsequent statements.
This seems to be the case as it still works after shutting down the database after converting the first statement.
But while inspecting what happens within the framework's source code, I found JdbcSchema#getRelDataType which seems to indicate that a connection to the database is needed every time.

Am I perhaps misunderstanding how the schema is accessed?

Thank you for your help!

Thomas Kirz