Generates code for this subtree.
Generates code for this subtree.
Adapted from WholeStageCodegenExec to allow running on executors.
the tuple of the codegen context and the actual generated source.
Create a DataSource for an external DataSource schema DDL string specification.
Prune all but the specified columns from the specified Catalyst schema.
Prune all but the specified columns from the specified Catalyst schema.
- The Catalyst column name to metadata of the master table
- The list of desired columns
A Catalyst schema corresponding to columns in the given order.
Utility methods used by external storage layers.