org.apache.calcite.rel.metadata

Interface BuiltInMetadata.MaxRowCount

All Superinterfaces:

Metadata

Enclosing class:

BuiltInMetadata

public static interface BuiltInMetadata.MaxRowCount
extends Metadata

Metadata about the maximum number of rows returned by a relational expression.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	BuiltInMetadata.MaxRowCount.Handler Handler API.

Field Summary

Fields

Modifier and Type	Field and Description
static MetadataDef<BuiltInMetadata.MaxRowCount>	DEF

Method Summary

Modifier and Type	Method and Description
@Nullable Double	getMaxRowCount() Estimates the max number of rows which will be returned by a relational expression.

Methods inherited from interface org.apache.calcite.rel.metadata.Metadata

rel

Field Detail

DEF

static final MetadataDef<BuiltInMetadata.MaxRowCount> DEF

Method Detail

getMaxRowCount

@Nullable Double getMaxRowCount()

Estimates the max number of rows which will be returned by a relational expression.

The default implementation for this query returns Double.POSITIVE_INFINITY, but metadata providers can override this with their own cost models.

Returns:

upper bound on the number of rows returned