ddl: initial support for parallel DDL (#6955)

ddl/column_test.go

@@ -61,8 +61,8 @@ func (s *testColumnSuite) TearDownSuite(c *C) {
 	testleak.AfterTest(c)()
 }
 
-func testCreateColumn(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo,
-	colName string, pos *ast.ColumnPosition, defaultValue interface{}) *model.Job {
+func buildCreateColumnJob(dbInfo *model.DBInfo, tblInfo *model.TableInfo, colName string,
+	pos *ast.ColumnPosition, defaultValue interface{}) *model.Job {
 	col := &model.ColumnInfo{
 		Name:               model.NewCIStr(colName),
 		Offset:             len(tblInfo.Columns),
@@ -79,22 +79,31 @@ func testCreateColumn(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo
 		BinlogInfo: &model.HistoryInfo{},
 		Args:       []interface{}{col, pos, 0},
 	}
+	return job
+}
 
+func testCreateColumn(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo,
+	colName string, pos *ast.ColumnPosition, defaultValue interface{}) *model.Job {
+	job := buildCreateColumnJob(dbInfo, tblInfo, colName, pos, defaultValue)
 	err := d.doDDLJob(ctx, job)
 	c.Assert(err, IsNil)
 	v := getSchemaVer(c, ctx)
 	checkHistoryJobArgs(c, ctx, job.ID, &historyJobArgs{ver: v, tbl: tblInfo})
 	return job
 }
 
-func testDropColumn(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo, colName string, isError bool) *model.Job {
-	job := &model.Job{
+func buildDropColumnJob(dbInfo *model.DBInfo, tblInfo *model.TableInfo, colName string) *model.Job {
+	return &model.Job{
 		SchemaID:   dbInfo.ID,
 		TableID:    tblInfo.ID,
 		Type:       model.ActionDropColumn,
 		BinlogInfo: &model.HistoryInfo{},
 		Args:       []interface{}{model.NewCIStr(colName)},
 	}
+}
+
+func testDropColumn(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo, colName string, isError bool) *model.Job {
+	job := buildDropColumnJob(dbInfo, tblInfo, colName)
 	err := d.doDDLJob(ctx, job)
 	if isError {
 		c.Assert(err, NotNil)

ddl/db_change_test.go

@@ -28,13 +28,13 @@ import (
 	"github.com/pingcap/tidb/executor"
 	"github.com/pingcap/tidb/infoschema"
 	"github.com/pingcap/tidb/kv"
-	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/model"
 	"github.com/pingcap/tidb/parser"
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/store/mockstore"
 	"github.com/pingcap/tidb/terror"
+	"github.com/pingcap/tidb/util/admin"
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testleak"
 	"golang.org/x/net/context"
@@ -580,15 +580,14 @@ func (s *testStateChangeSuite) testControlParallelExecSQL(c *C, sql1, sql2 strin
 		if times != 0 {
 			return
 		}
-		var qLen int64
-		var err1 error
+		var qLen int
 		for {
 			kv.RunInNewTxn(s.store, false, func(txn kv.Transaction) error {
-				m := meta.NewMeta(txn)
-				qLen, err1 = m.DDLJobQueueLen()
+				jobs, err1 := admin.GetDDLJobs(txn)
 				if err1 != nil {
 					return err1
 				}
+				qLen = len(jobs)
 				return nil
 			})
 			if qLen == 2 {

ddl/ddl.go

@@ -227,7 +227,7 @@ type ddl struct {
 	quitCh     chan struct{}
 
 	*ddlCtx
-	workers []*worker
+	workers map[workerType]*worker
 }
 
 // ddlCtx is the context when we use worker to handle DDL jobs.
@@ -236,7 +236,6 @@ type ddlCtx struct {
 	store        kv.Storage
 	ownerManager owner.Manager
 	schemaSyncer SchemaSyncer
-	ddlJobCh     chan struct{}
 	ddlJobDoneCh chan struct{}
 	ddlEventCh   chan<- *util.Event
 	lease        time.Duration // lease is schema lease.
@@ -317,7 +316,6 @@ func newDDL(ctx context.Context, etcdCli *clientv3.Client, store kv.Storage,
 		uuid:         id,
 		store:        store,
 		lease:        lease,
-		ddlJobCh:     make(chan struct{}, 1),
 		ddlJobDoneCh: make(chan struct{}, 1),
 		ownerManager: manager,
 		schemaSyncer: syncer,
@@ -359,20 +357,20 @@ func (d *ddl) start(ctx context.Context, ctxPool *pools.ResourcePool) {
 		err := d.ownerManager.CampaignOwner(ctx)
 		terror.Log(errors.Trace(err))
 
-		d.workers = make([]*worker, 1)
-		// TODO: Add addIdxWorker.
-		d.workers[0] = newWorker(generalWorker, 0, d.store, ctxPool)
+		d.workers = make(map[workerType]*worker, 2)
+		d.workers[generalWorker] = newWorker(generalWorker, 0, d.store, ctxPool)
+		d.workers[addIdxWorker] = newWorker(addIdxWorker, 1, d.store, ctxPool)
 		for _, worker := range d.workers {
 			worker.wg.Add(1)
 			go worker.start(d.ddlCtx)
 			// TODO: Add the type of DDL worker.
 			metrics.DDLCounter.WithLabelValues(metrics.CreateDDLWorker).Inc()
+
+			// When the start function is called, we will send a fake job to let worker
+			// checks owner firstly and try to find whether a job exists and run.
+			asyncNotify(worker.ddlJobCh)
 		}
 	}
-
-	// For every start, we will send a fake job to let worker
-	// check owner firstly and try to find whether a job exists and run.
-	asyncNotify(d.ddlJobCh)
 }
 
 func (d *ddl) close() {
@@ -418,16 +416,15 @@ func (d *ddl) genGlobalID() (int64, error) {
 		globalID, err = meta.NewMeta(txn).GenGlobalID()
 		return errors.Trace(err)
 	})
+
 	return globalID, errors.Trace(err)
 }
 
-// generalWorker returns the first worker. The ddl structure has only one worker before we implement the parallel worker.
+// generalWorker returns the general worker.
 // It's used for testing.
+// TODO: Remove this function.
 func (d *ddl) generalWorker() *worker {
-	if len(d.workers) == 0 {
-		return nil
-	}
-	return d.workers[0]
+	return d.workers[generalWorker]
 }
 
 // SchemaSyncer implements DDL.SchemaSyncer interface.
@@ -449,6 +446,19 @@ func checkJobMaxInterval(job *model.Job) time.Duration {
 	return 1 * time.Second
 }
 
+func (d *ddl) asyncNotifyWorker(jobTp model.ActionType) {
+	// If the workers don't run, we needn't to notify workers.
+	if !RunWorker {
+		return
+	}
+
+	if jobTp == model.ActionAddIndex {
+		asyncNotify(d.workers[addIdxWorker].ddlJobCh)
+	} else {
+		asyncNotify(d.workers[generalWorker].ddlJobCh)
+	}
+}
+
 func (d *ddl) doDDLJob(ctx sessionctx.Context, job *model.Job) error {
 	// For every DDL, we must commit current transaction.
 	if err := ctx.NewTxn(); err != nil {
@@ -463,7 +473,7 @@ func (d *ddl) doDDLJob(ctx sessionctx.Context, job *model.Job) error {
 	ctx.GetSessionVars().StmtCtx.IsDDLJobInQueue = true
 
 	// Notice worker that we push a new job and wait the job done.
-	asyncNotify(d.ddlJobCh)
+	d.asyncNotifyWorker(job.Type)
 	log.Infof("[ddl] start DDL job %s, Query:%s", job, job.Query)
 
 	var historyJob *model.Job

ddl/ddl_test.go

@@ -134,8 +134,8 @@ func checkHistoryJobArgs(c *C, ctx sessionctx.Context, id int64, args *historyJo
 	}
 }
 
-func testCreateIndex(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo, unique bool, indexName string, colName string) *model.Job {
-	job := &model.Job{
+func buildCreateIdxJob(dbInfo *model.DBInfo, tblInfo *model.TableInfo, unique bool, indexName string, colName string) *model.Job {
+	return &model.Job{
 		SchemaID:   dbInfo.ID,
 		TableID:    tblInfo.ID,
 		Type:       model.ActionAddIndex,
@@ -145,26 +145,42 @@ func testCreateIndex(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo,
 				Column: &ast.ColumnName{Name: model.NewCIStr(colName)},
 				Length: types.UnspecifiedLength}}},
 	}
+}
 
+func testCreateIndex(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo, unique bool, indexName string, colName string) *model.Job {
+	job := buildCreateIdxJob(dbInfo, tblInfo, unique, indexName, colName)
 	err := d.doDDLJob(ctx, job)
 	c.Assert(err, IsNil)
 	v := getSchemaVer(c, ctx)
 	checkHistoryJobArgs(c, ctx, job.ID, &historyJobArgs{ver: v, tbl: tblInfo})
 	return job
 }
 
-func testDropIndex(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo, indexName string) *model.Job {
-	job := &model.Job{
+func buildDropIdxJob(dbInfo *model.DBInfo, tblInfo *model.TableInfo, indexName string) *model.Job {
+	return &model.Job{
 		SchemaID:   dbInfo.ID,
 		TableID:    tblInfo.ID,
 		Type:       model.ActionDropIndex,
 		BinlogInfo: &model.HistoryInfo{},
 		Args:       []interface{}{model.NewCIStr(indexName)},
 	}
+}
 
+func testDropIndex(c *C, ctx sessionctx.Context, d *ddl, dbInfo *model.DBInfo, tblInfo *model.TableInfo, indexName string) *model.Job {
+	job := buildDropIdxJob(dbInfo, tblInfo, indexName)
 	err := d.doDDLJob(ctx, job)
 	c.Assert(err, IsNil)
 	v := getSchemaVer(c, ctx)
 	checkHistoryJobArgs(c, ctx, job.ID, &historyJobArgs{ver: v, tbl: tblInfo})
 	return job
 }
+
+func buildRebaseAutoIDJobJob(dbInfo *model.DBInfo, tblInfo *model.TableInfo, newBaseID int64) *model.Job {
+	return &model.Job{
+		SchemaID:   dbInfo.ID,
+		TableID:    tblInfo.ID,
+		Type:       model.ActionRebaseAutoID,
+		BinlogInfo: &model.HistoryInfo{},
+		Args:       []interface{}{newBaseID},
+	}
+}