github.com/whtcorpsinc/MilevaDB-Prod@v0.0.0-20211104133533-f57f4be3b597/interlock/aggfuncs/aggfuncs.go

// Copyright 2020 WHTCORPS INC, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package aggfuncs

import (
	"unsafe"

	"github.com/whtcorpsinc/milevadb/memex"
	"github.com/whtcorpsinc/milevadb/stochastikctx"
	"github.com/whtcorpsinc/milevadb/soliton/chunk"
)

// All the AggFunc implementations are listed here for navigation.
var (
	// All the AggFunc implementations for "COUNT" are listed here.
	_ AggFunc = (*countPartial)(nil)
	_ AggFunc = (*countOriginal4Int)(nil)
	_ AggFunc = (*countOriginal4Real)(nil)
	_ AggFunc = (*countOriginal4Decimal)(nil)
	_ AggFunc = (*countOriginal4Time)(nil)
	_ AggFunc = (*countOriginal4Duration)(nil)
	_ AggFunc = (*countOriginal4JSON)(nil)
	_ AggFunc = (*countOriginal4String)(nil)
	_ AggFunc = (*countOriginalWithDistinct4Int)(nil)
	_ AggFunc = (*countOriginalWithDistinct4Real)(nil)
	_ AggFunc = (*countOriginalWithDistinct4Decimal)(nil)
	_ AggFunc = (*countOriginalWithDistinct4Duration)(nil)
	_ AggFunc = (*countOriginalWithDistinct4String)(nil)
	_ AggFunc = (*countOriginalWithDistinct)(nil)

	// All the AggFunc implementations for "APPROX_COUNT_DISTINCT" are listed here.
	_ AggFunc = (*approxCountDistinctOriginal)(nil)
	_ AggFunc = (*approxCountDistinctPartial1)(nil)
	_ AggFunc = (*approxCountDistinctPartial2)(nil)
	_ AggFunc = (*approxCountDistinctFinal)(nil)

	// All the AggFunc implementations for "FIRSTROW" are listed here.
	_ AggFunc = (*firstEvent4Decimal)(nil)
	_ AggFunc = (*firstEvent4Int)(nil)
	_ AggFunc = (*firstEvent4Time)(nil)
	_ AggFunc = (*firstEvent4String)(nil)
	_ AggFunc = (*firstEvent4Duration)(nil)
	_ AggFunc = (*firstEvent4Float32)(nil)
	_ AggFunc = (*firstEvent4Float64)(nil)
	_ AggFunc = (*firstEvent4JSON)(nil)
	_ AggFunc = (*firstEvent4Enum)(nil)
	_ AggFunc = (*firstEvent4Set)(nil)

	// All the AggFunc implementations for "MAX"/"MIN" are listed here.
	_ AggFunc = (*maxMin4Int)(nil)
	_ AggFunc = (*maxMin4Uint)(nil)
	_ AggFunc = (*maxMin4Float32)(nil)
	_ AggFunc = (*maxMin4Float64)(nil)
	_ AggFunc = (*maxMin4Decimal)(nil)
	_ AggFunc = (*maxMin4String)(nil)
	_ AggFunc = (*maxMin4Duration)(nil)
	_ AggFunc = (*maxMin4JSON)(nil)
	_ AggFunc = (*maxMin4Enum)(nil)
	_ AggFunc = (*maxMin4Set)(nil)

	// All the AggFunc implementations for "AVG" are listed here.
	_ AggFunc = (*avgOriginal4Decimal)(nil)
	_ AggFunc = (*avgOriginal4DistinctDecimal)(nil)
	_ AggFunc = (*avgPartial4Decimal)(nil)

	_ AggFunc = (*avgOriginal4Float64)(nil)
	_ AggFunc = (*avgPartial4Float64)(nil)
	_ AggFunc = (*avgOriginal4DistinctFloat64)(nil)

	// All the AggFunc implementations for "SUM" are listed here.
	_ AggFunc = (*sum4DistinctFloat64)(nil)
	_ AggFunc = (*sum4DistinctDecimal)(nil)
	_ AggFunc = (*sum4Decimal)(nil)
	_ AggFunc = (*sum4Float64)(nil)

	// All the AggFunc implementations for "GROUP_CONCAT" are listed here.
	_ AggFunc = (*groupConcatDistinct)(nil)
	_ AggFunc = (*groupConcat)(nil)

	// All the AggFunc implementations for "BIT_OR" are listed here.
	_ AggFunc = (*bitOrUint64)(nil)

	// All the AggFunc implementations for "BIT_XOR" are listed here.
	_ AggFunc = (*bitXorUint64)(nil)

	// All the AggFunc implementations for "BIT_AND" are listed here.
	_ AggFunc = (*bitAndUint64)(nil)

	// All the AggFunc implementations for "JSON_OBJECTAGG" are listed here
	_ AggFunc = (*jsonObjectAgg)(nil)
)

const (
	// DefUint32Size is the size of uint32
	DefUint32Size = int64(unsafe.Sizeof(uint32(0)))
	// DefUint64Size is the size of uint64
	DefUint64Size = int64(unsafe.Sizeof(uint64(0)))
	// DefInt64Size is the size of int64
	DefInt64Size = int64(unsafe.Sizeof(int64(0)))
	// DefFloat64Size is the size of float64
	DefFloat64Size = int64(unsafe.Sizeof(float64(0)))
	// DefTimeSize is the size of time
	DefTimeSize = int64(16)
	// DefEventSize is the size of event
	DefEventSize = int64(unsafe.Sizeof(chunk.Event{}))
)

// PartialResult represents data structure to causetstore the partial result for the
// aggregate functions. Here we use unsafe.Pointer to allow the partial result
// to be any type.
type PartialResult unsafe.Pointer

// AggFunc is the interface to evaluate the aggregate functions.
type AggFunc interface {
	// AllocPartialResult allocates a specific data structure to causetstore the
	// partial result, initializes it, and converts it to PartialResult to
	// return back. The second returned value is the memDelta used to trace
	// memory usage. Aggregate operator implementation, no matter it's a hash
	// or stream, should hold this allocated PartialResult for the further
	// operations like: "ResetPartialResult", "UFIDelatePartialResult".
	AllocPartialResult() (pr PartialResult, memDelta int64)

	// ResetPartialResult resets the partial result to the original state for a
	// specific aggregate function. It converts the input PartialResult to the
	// specific data structure which stores the partial result and then reset
	// every field to the proper original state.
	ResetPartialResult(pr PartialResult)

	// UFIDelatePartialResult uFIDelates the specific partial result for an aggregate
	// function using the input rows which all belonging to the same data group.
	// It converts the PartialResult to the specific data structure which stores
	// the partial result and then iterates on the input rows and uFIDelate that
	// partial result according to the functionality and the state of the
	// aggregate function. The returned value is the memDelta used to trace memory
	// usage.
	UFIDelatePartialResult(sctx stochastikctx.Context, rowsInGroup []chunk.Event, pr PartialResult) (memDelta int64, err error)

	// MergePartialResult will be called in the final phase when parallelly
	// executing. It converts the PartialResult `src`, `dst` to the same specific
	// data structure which stores the partial results, and then evaluate the
	// final result using the partial results as input values. The returned value
	// is the memDelta used to trace memory usage.
	MergePartialResult(sctx stochastikctx.Context, src, dst PartialResult) (memDelta int64, err error)

	// AppendFinalResult2Chunk finalizes the partial result and append the
	// final result to the input chunk. Like other operations, it converts the
	// input PartialResult to the specific data structure which stores the
	// partial result and then calculates the final result and append that
	// final result to the chunk provided.
	AppendFinalResult2Chunk(sctx stochastikctx.Context, pr PartialResult, chk *chunk.Chunk) error
}

type baseAggFunc struct {
	// args stores the input arguments for an aggregate function, we should
	// call arg.EvalXXX to get the actual input data for this function.
	args []memex.Expression

	// ordinal stores the ordinal of the defCausumns in the output chunk, which is
	// used to append the final result of this function.
	ordinal int
}

func (*baseAggFunc) MergePartialResult(sctx stochastikctx.Context, src, dst PartialResult) (memDelta int64, err error) {
	return 0, nil
}

// SlidingWindowAggFunc is the interface to evaluate the aggregate functions using sliding window.
type SlidingWindowAggFunc interface {
	// Slide evaluates the aggregate functions using a sliding window. The input
	// lastStart and lastEnd are the interval of the former sliding window,
	// shiftStart, shiftEnd mean the sliding window offset. Note that the input
	// PartialResult stores the intermediate result which will be used in the next
	// sliding window, ensure call ResetPartialResult after a frame are evaluated
	// completely.
	Slide(sctx stochastikctx.Context, rows []chunk.Event, lastStart, lastEnd uint64, shiftStart, shiftEnd uint64, pr PartialResult) error
}