DRILL-7095: Expose table schema (TupleMetadata) to physical operator (EasySubScan) 1. Add system / session option store.table.use_schema_file to control if file schema can be used during query execution. False by default. 2. Added methods in StoragePlugin interface which allow to create Group Scan with provided table schema. 3. EasyGroupScan and EasySubScan now contain table schema, also they are able to serialize / deserialize it along with other scan properties. 4. DrillTable which is the main entry point for schema provisioning, has method to store schema and later uses it to create physical scan. 5. WorkspaceSchema when returning Drill table instance will get table schema from table root if available and if store.table.use_schema_file is set to true.
This PR is the next step for Schema Provisioning project which currently exposes schema only for text reader.
DRILL-6952: Host compliant text reader on the row set framework The result set loader allows controlling batch sizes. The new scan framework built on top of that framework handles projection, implicit columns, null columns and more. This commit converts the "new" ("compliant") text reader to use the new framework. Options select the use of the V2 ("new") or V3 (row-set based) versions. Unit tests demonstrate V3 functionality.