org.apache.calcite.rel.metadata

Interface BuiltInMetadata.Memory

All Superinterfaces:

Metadata

Enclosing class:

BuiltInMetadata

public static interface BuiltInMetadata.Memory
extends Metadata

Metadata about the memory use of an operator.

Method Summary

Methods

Modifier and Type	Method and Description
Double	cumulativeMemoryWithinPhase() Returns the cumulative amount of memory, in bytes, required by the physical operator implementing this relational expression, and all other operators within the same phase, across all splits.
Double	cumulativeMemoryWithinPhaseSplit() Returns the expected cumulative amount of memory, in bytes, required by the physical operator implementing this relational expression, and all operators within the same phase, within each split.
Double	memory() Returns the expected amount of memory, in bytes, required by a physical operator implementing this relational expression, across all splits.

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

rel

Method Detail

memory

Double memory()

Returns the expected amount of memory, in bytes, required by a physical operator implementing this relational expression, across all splits.

How much memory is used depends very much on the algorithm; for example, an implementation of Aggregate that loads all data into a hash table requires approximately rowCount * averageRowSize bytes, whereas an implementation that assumes that the input is sorted requires only averageRowSize bytes to maintain a single accumulator for each aggregate function.

cumulativeMemoryWithinPhase

Double cumulativeMemoryWithinPhase()

Returns the cumulative amount of memory, in bytes, required by the physical operator implementing this relational expression, and all other operators within the same phase, across all splits.

See Also:

BuiltInMetadata.Parallelism.splitCount()

cumulativeMemoryWithinPhaseSplit

Double cumulativeMemoryWithinPhaseSplit()

Returns the expected cumulative amount of memory, in bytes, required by the physical operator implementing this relational expression, and all operators within the same phase, within each split.

Basic formula:

cumulativeMemoryWithinPhaseSplit = cumulativeMemoryWithinPhase / Parallelism.splitCount