ddl: support pre-split index regions before creating index

pkg/ddl/BUILD.bazel

@@ -43,6 +43,7 @@ go_library(
         "index.go",
         "index_cop.go",
         "index_merge_tmp.go",
+        "index_presplit.go",
         "job_scheduler.go",
         "job_submitter.go",
         "job_worker.go",
@@ -152,6 +153,7 @@ go_library(
         "//pkg/util/context",
         "//pkg/util/dbterror",
         "//pkg/util/dbterror/exeerrors",
+        "//pkg/util/dbterror/plannererrors",
         "//pkg/util/domainutil",
         "//pkg/util/engine",
         "//pkg/util/execdetails",

pkg/ddl/backfilling.go

@@ -244,7 +244,6 @@ type reorgBackfillTask struct {
 	startKey kv.Key
 	endKey   kv.Key
 	jobID    int64
-	sqlQuery string
 	priority int
 }
 

pkg/ddl/executor.go

@@ -48,6 +48,7 @@ import (
 	"github.com/pingcap/tidb/pkg/metrics"
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/charset"
+	"github.com/pingcap/tidb/pkg/parser/format"
 	pmodel "github.com/pingcap/tidb/pkg/parser/model"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
 	"github.com/pingcap/tidb/pkg/parser/terror"
@@ -4611,6 +4612,10 @@ func (e *executor) CreatePrimaryKey(ctx sessionctx.Context, ti ast.Ident, indexN
 		}
 	}
 
+	splitOpt, err := buildIndexPresplitOpt(indexOption)
+	if err != nil {
+		return errors.Trace(err)
+	}
 	sqlMode := ctx.GetSessionVars().SQLMode
 	// global is set to  'false' is just there to be backwards compatible,
 	// to avoid unmarshal issues, it is now part of indexOption.
@@ -4637,6 +4642,7 @@ func (e *executor) CreatePrimaryKey(ctx sessionctx.Context, ti ast.Ident, indexN
 			SQLMode:                 sqlMode,
 			Global:                  false,
 			IsPK:                    true,
+			SplitOpt:                splitOpt,
 		}},
 		OpType: model.OpAddIndex,
 	}
@@ -4884,6 +4890,11 @@ func (e *executor) createIndex(ctx sessionctx.Context, ti ast.Ident, keyType ast
 		return e.addHypoIndexIntoCtx(ctx, ti.Schema, ti.Name, indexInfo)
 	}
 
+	splitOpt, err := buildIndexPresplitOpt(indexOption)
+	if err != nil {
+		return errors.Trace(err)
+	}
+
 	// global is set to  'false' is just there to be backwards compatible,
 	// to avoid unmarshal issues, it is now part of indexOption.
 	global := false
@@ -4906,6 +4917,7 @@ func (e *executor) createIndex(ctx sessionctx.Context, ti ast.Ident, keyType ast
 			IndexOption:             indexOption,
 			HiddenCols:              hiddenCols,
 			Global:                  global,
+			SplitOpt:                splitOpt,
 		}},
 		OpType: model.OpAddIndex,
 	}
@@ -4995,6 +5007,56 @@ func initJobReorgMetaFromVariables(job *model.Job, sctx sessionctx.Context) erro
 	return nil
 }
 
+func buildIndexPresplitOpt(indexOpt *ast.IndexOption) (*model.IndexArgSplitOpt, error) {
+	if indexOpt == nil {
+		return nil, nil
+	}
+	opt := indexOpt.SplitOpt
+	if opt == nil {
+		return nil, nil
+	}
+	lowers := make([]string, 0, len(opt.Lower))
+	for _, expL := range opt.Lower {
+		var sb strings.Builder
+		rCtx := format.NewRestoreCtx(format.DefaultRestoreFlags, &sb)
+		err := expL.Restore(rCtx)
+		if err != nil {
+			return nil, errors.Trace(err)
+		}
+		lowers = append(lowers, sb.String())
+	}
+	uppers := make([]string, 0, len(opt.Upper))
+	for _, expU := range opt.Upper {
+		var sb strings.Builder
+		rCtx := format.NewRestoreCtx(format.DefaultRestoreFlags, &sb)
+		err := expU.Restore(rCtx)
+		if err != nil {
+			return nil, errors.Trace(err)
+		}
+		uppers = append(uppers, sb.String())
+	}
+	valLists := make([][]string, 0, len(opt.ValueLists))
+	for _, lst := range opt.ValueLists {
+		values := make([]string, 0, len(lst))
+		for _, exp := range lst {
+			var sb strings.Builder
+			rCtx := format.NewRestoreCtx(format.DefaultRestoreFlags, &sb)
+			err := exp.Restore(rCtx)
+			if err != nil {
+				return nil, errors.Trace(err)
+			}
+			values = append(values, sb.String())
+		}
+		valLists = append(valLists, values)
+	}
+	return &model.IndexArgSplitOpt{
+		Lower:      lowers,
+		Upper:      uppers,
+		Num:        opt.Num,
+		ValueLists: valLists,
+	}, nil
+}
+
 // LastReorgMetaFastReorgDisabled is used for test.
 var LastReorgMetaFastReorgDisabled bool
 

pkg/ddl/index.go

@@ -993,6 +993,13 @@ SwitchIndexState:
 				indexInfo.BackfillState = model.BackfillStateRunning
 			}
 		}
+		err = presplitIndexRegions(jobCtx.stepCtx, w.sess.Context, w.store, tblInfo, allIndexInfos, job.ReorgMeta, args)
+		if err != nil {
+			if !isRetryableJobError(err, job.ErrorCount) {
+				job.State = model.JobStateCancelled
+			}
+			return ver, err
+		}
 		for _, indexInfo := range allIndexInfos {
 			indexInfo.State = model.StateDeleteOnly
 			moveAndUpdateHiddenColumnsToPublic(tblInfo, indexInfo)