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MergedAggregate implements AggregatingFunction

FinalYes

Reads the column $aggregate->outputName() as partials and merges them; its output is $aggregate's value(), so wave 2 of a shuffle and the parent's finisher reuse the group-by processor unchanged.

Interfaces

AggregatingFunction

Methods

__construct() : mixed
aggregate() : void
children() : array<int, FunctionTree>: The inner aggregator is resolved already; the resolver must not touch it.
describe() : null|Description
deterministic() : bool: True when this node and every node in children() produce the same value for the same input row.
fromDescription() : static
merge() : void: Folds a partial() of another instance into this one; that instance aggregated rows that come after this one's (merge()'s contract).
outputName() : string: Decided in the constructor, never mutated.
partial() : array<string, mixed>: This aggregator's state as plain values of partialType(); an aggregator that saw no row returns its initial state.
partialType() : StructureType<string|int, array<string, mixed>>: The structure partial() returns; valid once the aggregator is resolved (Aggregators::resolved()).
references() : null|array<int, Reference>
resolved() : bool: True when this node and every node in children() can answer returns().
returns() : Type<string|int, mixed>: An OptionalType return declares the produced column nullable; there is no nullable() peer.
value() : null|array<string|int, mixed>|bool|float|int|object|string
withChildren() : static: A fresh inner aggregator, as Aggregators::fresh() needs.

__construct()


    public
                    __construct(AggregatingFunction $aggregate) : mixed

Parameters

$aggregate : AggregatingFunction: resolved against the plan's input schema

aggregate()


    public
                    aggregate(Rows $rows, array<string|int, mixed> $indices, Backend $backend) : void

Parameters

$rows : Rows
$indices : array<string|int, mixed>: the rows of $rows that belong to this aggregate, ascending
$backend : Backend

children()

The inner aggregator is resolved already; the resolver must not touch it.


    public
                    children() : array<int, FunctionTree>

Return values

array<int, FunctionTree>

describe()


    public
                    describe() : null|Description

Return values

null|Description —

null when this instance cannot cross a process boundary (a live client, a custom collaborator)

deterministic()

True when this node and every node in children() produce the same value for the same input row.


    public
                    deterministic() : bool

False for a generator (now(), uuid, a random string): a caller that evaluates the tree once per FILE or per partition instead of once per row must refuse a non-deterministic one.

Return values

bool

fromDescription()


    public
            static        fromDescription(array<string|int, mixed> $data, Rebuild $rebuild) : static

Parameters

$data : array<string|int, mixed>
$rebuild : Rebuild

Return values

static

merge()

Folds a partial() of another instance into this one; that instance aggregated rows that come after this one's (merge()'s contract).


    public
                    merge(array<string|int, mixed> $partial, Backend $backend) : void

Parameters

$partial : array<string|int, mixed>
$backend : Backend

outputName()

Decided in the constructor, never mutated.


    public
                    outputName() : string

Return values

string

partial()

This aggregator's state as plain values of partialType(); an aggregator that saw no row returns its initial state.


    public
                    partial() : array<string, mixed>

Return values

array<string, mixed>

partialType()

The structure partial() returns; valid once the aggregator is resolved (Aggregators::resolved()).


    public
                    partialType() : StructureType<string|int, array<string, mixed>>

Return values

StructureType<string|int, array<string, mixed>>

references()


    public
                    references() : null|array<int, Reference>

Return values

null|array<int, Reference> —

references this aggregator reads, or null when they cannot be statically enumerated (disables spill column pruning)

resolved()

True when this node and every node in children() can answer returns().


    public
                    resolved() : bool

Return values

bool

returns()

An OptionalType return declares the produced column nullable; there is no nullable() peer.


    public
                    returns() : Type<string|int, mixed>

Return values

Type<string|int, mixed>

value()


    public
                    value() : null|array<string|int, mixed>|bool|float|int|object|string

Return values

withChildren()

A fresh inner aggregator, as Aggregators::fresh() needs.


    public
                    withChildren(array<string|int, mixed> $children) : static

Parameters

$children : array<string|int, mixed>

Return values

static