TypedImperativeAggregate — Contract for Imperative Aggregate Functions with Custom Aggregation Buffer

TypedImperativeAggregate is the contract for imperative aggregation functions that allows for an arbitrary user-defined java object to be used as internal aggregation buffer.

Table 1. TypedImperativeAggregate as ImperativeAggregate
ImperativeAggregate Method Description

aggBufferAttributes

aggBufferSchema

initialize

Creates an aggregation buffer and puts it at mutableAggBufferOffset position in the input buffer InternalRow.

inputAggBufferAttributes
Table 2. TypedImperativeAggregate’s Direct Implementations
Name Description

ApproximatePercentile

Collect

ComplexTypedAggregateExpression

CountMinSketchAgg

HiveUDAFFunction

Percentile

TypedImperativeAggregate Contract

package org.apache.spark.sql.catalyst.expressions.aggregate

abstract class TypedImperativeAggregate[T] extends ImperativeAggregate {
  def createAggregationBuffer(): T
  def deserialize(storageFormat: Array[Byte]): T
  def eval(buffer: T): Any
  def merge(buffer: T, input: T): T
  def serialize(buffer: T): Array[Byte]
  def update(buffer: T, input: InternalRow): T
}
Table 3. TypedImperativeAggregate Contract
Method Description

createAggregationBuffer

Used exclusively when a TypedImperativeAggregate is initialized

deserialize

eval

merge

serialize

update

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