Package org.apache.drill.exec.physical.impl.scan.v3
package org.apache.drill.exec.physical.impl.scan.v3
Provides the "version 3" scan framework (which can also be thought of
as EVF version 2). This version provides basically the same API as
version 2, but with an implementation driven by schema rather than
vectors.
Build a scan using the ScanLifecycleBuilder. Provide a subclass
of ReaderFactory that will create each of your
ManagedReader instances as needed. The framework handles the
details of schemas, missing columns, implicit columns and the rest.
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ClassDescriptionLayer above the
ResultSetLoaderwhich handles standard conversions for scalar columns where the schema is known up front (i.e.Extended version of a record reader which uses a size-aware batch mutator.Exception thrown from the constructor if the data source is empty and can produce no data or schema.ReaderFactory<T extends SchemaNegotiator>Creates a batch reader on demand.Gathers options for theScanLifecyclethen builds a scan lifecycle instance.Negotiates the table schema with the scanner framework and provides context information for the reader.