org.apache.flink.table.planner.typeutils

Class DataViewUtils

java.lang.Object

org.apache.flink.table.planner.typeutils.DataViewUtils

@Internal
public final class DataViewUtils
extends Object

Utilities to deal with DataViews.

A DataView is either represented as a regular StructuredType or as a RawType that serializes to null when backed by a state backend. In the latter case, a DataViewSpec contains all information necessary to store and retrieve data from state.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DataViewUtils.DistinctViewSpec Specification for a special MapView for deduplication.

Method Summary

Modifier and Type	Method and Description
static DataType	adjustDataViews(DataType accumulatorDataType, boolean hasStateBackedDataViews) Modifies the data type of an accumulator regarding data views.
static DataType	createDistinctViewDataType(DataType keyDataType, int filterArgs, int filterArgsLimit) Creates a special DataType for DISTINCT aggregates.
static DataViewUtils.DistinctViewSpec	createDistinctViewSpec(int index, DataType distinctViewDataType) Creates a special DataViewUtils.DistinctViewSpec for DISTINCT aggregates.
static List<DataViewSpec>	extractDataViews(int aggIndex, DataType accumulatorDataType) Searches for data views in the data type of an accumulator and extracts them.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

extractDataViews

public static List<DataViewSpec> extractDataViews(int aggIndex,
                                                  DataType accumulatorDataType)

Searches for data views in the data type of an accumulator and extracts them.

adjustDataViews

public static DataType adjustDataViews(DataType accumulatorDataType,
                                       boolean hasStateBackedDataViews)

Modifies the data type of an accumulator regarding data views.

For performance reasons, each data view is wrapped into a RAW type which gives it LazyBinaryFormat semantics and avoids multiple deserialization steps during access. Furthermore, a data view will not be serialized if a state backend is used (the serializer of the RAW type will be a NullSerializer in this case).

createDistinctViewDataType

public static DataType createDistinctViewDataType(DataType keyDataType,
                                                  int filterArgs,
                                                  int filterArgsLimit)

Creates a special DataType for DISTINCT aggregates.

createDistinctViewSpec

public static DataViewUtils.DistinctViewSpec createDistinctViewSpec(int index,
                                                                    DataType distinctViewDataType)

Creates a special DataViewUtils.DistinctViewSpec for DISTINCT aggregates.