github.com/pingcap/tidb/parser@v0.0.0-20231013125129-93a834a6bf8d/model/reorg.go

// Copyright 2023 PingCAP, 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 model

import (
	"encoding/json"

	"github.com/pingcap/errors"
	"github.com/pingcap/tidb/parser/mysql"
	"github.com/pingcap/tidb/parser/terror"
)

// DDLReorgMeta is meta info of DDL reorganization.
type DDLReorgMeta struct {
	SQLMode           mysql.SQLMode                    `json:"sql_mode"`
	Warnings          map[errors.ErrorID]*terror.Error `json:"warnings"`
	WarningsCount     map[errors.ErrorID]int64         `json:"warnings_count"`
	Location          *TimeZoneLocation                `json:"location"`
	ReorgTp           ReorgType                        `json:"reorg_tp"`
	IsDistReorg       bool                             `json:"is_dist_reorg"`
	ResourceGroupName string                           `json:"resource_group_name"`
}

// ReorgType indicates which process is used for the data reorganization.
type ReorgType int8

const (
	// ReorgTypeNone means the backfill task is not started yet.
	ReorgTypeNone ReorgType = iota
	// ReorgTypeTxn means the index records are backfill with transactions.
	// All the index KVs are written through the transaction interface.
	// This is the original backfill implementation.
	ReorgTypeTxn
	// ReorgTypeLitMerge means the index records are backfill with lightning.
	// The index KVs are encoded to SST files and imported to the storage directly.
	// The incremental index KVs written by DML are redirected to a temporary index.
	// After the backfill is finished, the temporary index records are merged back to the original index.
	ReorgTypeLitMerge
	// ReorgTypeTxnMerge means backfill with transactions and merge incremental changes.
	// The backfill index KVs are written through the transaction interface.
	// The incremental index KVs written by DML are redirected to a temporary index.
	// After the backfill is finished, the temporary index records are merged back to the original index.
	ReorgTypeTxnMerge
)

// NeedMergeProcess means the incremental changes need to be merged.
func (tp ReorgType) NeedMergeProcess() bool {
	return tp == ReorgTypeLitMerge || tp == ReorgTypeTxnMerge
}

// String implements fmt.Stringer interface.
func (tp ReorgType) String() string {
	switch tp {
	case ReorgTypeTxn:
		return "txn"
	case ReorgTypeLitMerge:
		return "ingest"
	case ReorgTypeTxnMerge:
		return "txn-merge"
	}
	return ""
}

// BackfillState is the state used by the backfill-merge process.
type BackfillState byte

const (
	// BackfillStateInapplicable means the backfill-merge process is not used.
	BackfillStateInapplicable BackfillState = iota
	// BackfillStateRunning is the state that the backfill process is running.
	// In this state, the index's write and delete operations are redirected to a temporary index.
	BackfillStateRunning
	// BackfillStateReadyToMerge is the state that the temporary index's records are ready to be merged back
	// to the origin index.
	// In this state, the index's write and delete operations are copied to a temporary index.
	// This state is used to make sure that all the TiDB instances are aware of the copy
	// during the merge(BackfillStateMerging).
	BackfillStateReadyToMerge
	// BackfillStateMerging is the state that the temp index is merging back to the origin index.
	// In this state, the index's write and delete operations are copied to a temporary index.
	BackfillStateMerging
)

// String implements fmt.Stringer interface.
func (s BackfillState) String() string {
	switch s {
	case BackfillStateRunning:
		return "backfill state running"
	case BackfillStateReadyToMerge:
		return "backfill state ready to merge"
	case BackfillStateMerging:
		return "backfill state merging"
	case BackfillStateInapplicable:
		return "backfill state inapplicable"
	default:
		return "backfill state unknown"
	}
}

// BackfillMeta is meta info of the backfill job.
type BackfillMeta struct {
	IsUnique   bool          `json:"is_unique"`
	EndInclude bool          `json:"end_include"`
	Error      *terror.Error `json:"err"`

	SQLMode       mysql.SQLMode                    `json:"sql_mode"`
	Warnings      map[errors.ErrorID]*terror.Error `json:"warnings"`
	WarningsCount map[errors.ErrorID]int64         `json:"warnings_count"`
	Location      *TimeZoneLocation                `json:"location"`
	ReorgTp       ReorgType                        `json:"reorg_tp"`
	RowCount      int64                            `json:"row_count"`
	StartKey      []byte                           `json:"start_key"`
	EndKey        []byte                           `json:"end_key"`
	CurrKey       []byte                           `json:"curr_key"`
	*JobMeta      `json:"job_meta"`
}

// Encode encodes BackfillMeta with json format.
func (bm *BackfillMeta) Encode() ([]byte, error) {
	b, err := json.Marshal(bm)
	return b, errors.Trace(err)
}

// Decode decodes BackfillMeta from the json buffer.
func (bm *BackfillMeta) Decode(b []byte) error {
	err := json.Unmarshal(b, bm)
	return errors.Trace(err)
}