TypedImperativeAggregate Expressions¶

TypedImperativeAggregate is an extension of the ImperativeAggregate abstraction for typed ImperativeAggregates.

Scala Definition

TypedImperativeAggregate[T] is a type constructor (Scala) with T type parameter.

Contract¶

Creating Aggregation Buffer¶

createAggregationBuffer(): T

Creates an empty aggregation buffer object (to initialize this TypedImperativeAggregate)

See:

Used when:

Collect is requested to deserialize
TypedImperativeAggregate is requested to initialize

Deserializing¶

deserialize(
  storageFormat: Array[Byte]): T

See:

Used when:

TypedImperativeAggregate is requested to merge

Interpreted Execution¶

eval(
  buffer: T): Any

See:

Used when:

TypedImperativeAggregate is requested to execute (interpreted mode)

merge¶

merge(
  buffer: T,
  input: T): T

See:

Used when:

TypedImperativeAggregate is requested to merge and mergeBuffersObjects

Serializing Aggregate Buffer¶

serialize(
  buffer: T): Array[Byte]

See:

Used when:

TypedImperativeAggregate is requested to serialize the aggregate buffer in-place

update¶

update(
  buffer: T,
  input: InternalRow): T

See:

Used when:

TypedImperativeAggregate is requested to update

Implementations¶

Interpreted Expression Evaluation¶

Expression

eval(
  buffer: InternalRow): Any

eval is part of the Expression abstraction.

eval take the buffer object out of the given InternalRow and evaluates the result.

Aggregate Buffer Attributes¶

AggregateFunction

aggBufferAttributes: Seq[AttributeReference]

aggBufferAttributes is part of the AggregateFunction abstraction.

aggBufferAttributes is a single AttributeReference:

Name	DataType
`buf`	BinaryType

Extracting Aggregate Buffer Object¶

getBufferObject(
  bufferRow: InternalRow): T // (1)!
getBufferObject(
  buffer: InternalRow,
  offset: Int): T

Uses the mutableAggBufferOffset as the offset

getBufferObject requests the given InternalRow for the value (of type T) at the given offset that is of ObjectType type.

getBufferObject is used when:

TypedImperativeAggregate is requested to mergeBuffersObjects, update, merge, eval, serializeAggregateBufferInPlace

ObjectType¶

anyObjectType: ObjectType

When created, TypedImperativeAggregate creates an ObjectType of a value of Scala AnyRef type.

The ObjectType is used in getBufferObject.

Serializing Aggregate Buffer In-Place¶

serializeAggregateBufferInPlace(
  buffer: InternalRow): Unit

Procedure

serializeAggregateBufferInPlace is a procedure (returns Unit) so whatever happens inside, stays inside (paraphrasing the former advertising slogan of Las Vegas, Nevada).

serializeAggregateBufferInPlace gets the aggregate buffer from the given buffer and serializes it.

In the end, serializeAggregateBufferInPlace stores the serialized aggregate buffer back to the given buffer at mutableAggBufferOffset.

serializeAggregateBufferInPlace is used when:

AggregatingAccumulator is requested to withBufferSerialized
AggregationIterator is requested to generateResultProjection
ObjectAggregationMap is requested to dumpToExternalSorter