domain: fix updating the self schema version and update log (#10324) (#…

…10359)

domain/domain.go

@@ -82,40 +82,47 @@ func (do *Domain) loadInfoSchema(handle *infoschema.Handle, usedSchemaVersion in
 		return 0, nil, fullLoad, errors.Trace(err)
 	}
 	m := meta.NewSnapshotMeta(snapshot)
-	latestSchemaVersion, err := m.GetSchemaVersion()
+	neededSchemaVersion, err := m.GetSchemaVersion()
 	if err != nil {
 		return 0, nil, fullLoad, errors.Trace(err)
 	}
-	if usedSchemaVersion != 0 && usedSchemaVersion == latestSchemaVersion {
-		return latestSchemaVersion, nil, fullLoad, nil
+	if usedSchemaVersion != 0 && usedSchemaVersion == neededSchemaVersion {
+		return neededSchemaVersion, nil, fullLoad, nil
 	}
 
 	// Update self schema version to etcd.
 	defer func() {
-		if err != nil {
-			logutil.Logger(context.Background()).Info("cannot update self schema version to etcd")
+		// There are two possibilities for not updating the self schema version to etcd.
+		// 1. Failed to loading schema information.
+		// 2. When users use history read feature, the neededSchemaVersion isn't the latest schema version.
+		if err != nil || neededSchemaVersion < do.InfoSchema().SchemaMetaVersion() {
+			logutil.Logger(context.Background()).Info("do not update self schema version to etcd",
+				zap.Int64("usedSchemaVersion", usedSchemaVersion),
+				zap.Int64("neededSchemaVersion", neededSchemaVersion), zap.Error(err))
 			return
 		}
-		err = do.ddl.SchemaSyncer().UpdateSelfVersion(context.Background(), latestSchemaVersion)
+
+		err = do.ddl.SchemaSyncer().UpdateSelfVersion(context.Background(), neededSchemaVersion)
 		if err != nil {
-			logutil.Logger(context.Background()).Info("update self version failed", zap.Int64("usedSchemaVersion", usedSchemaVersion),
-				zap.Int64("latestSchemaVersion", latestSchemaVersion), zap.Error(err))
+			logutil.Logger(context.Background()).Info("update self version failed",
+				zap.Int64("usedSchemaVersion", usedSchemaVersion),
+				zap.Int64("neededSchemaVersion", neededSchemaVersion), zap.Error(err))
 		}
 	}()
 
 	startTime := time.Now()
-	ok, tblIDs, err := do.tryLoadSchemaDiffs(m, usedSchemaVersion, latestSchemaVersion)
+	ok, tblIDs, err := do.tryLoadSchemaDiffs(m, usedSchemaVersion, neededSchemaVersion)
 	if err != nil {
 		// We can fall back to full load, don't need to return the error.
 		logutil.Logger(context.Background()).Error("failed to load schema diff", zap.Error(err))
 	}
 	if ok {
 		logutil.Logger(context.Background()).Info("diff load InfoSchema success",
 			zap.Int64("usedSchemaVersion", usedSchemaVersion),
-			zap.Int64("latestSchemaVersion", latestSchemaVersion),
+			zap.Int64("neededSchemaVersion", neededSchemaVersion),
 			zap.Duration("start time", time.Since(startTime)),
 			zap.Int64s("tblIDs", tblIDs))
-		return latestSchemaVersion, tblIDs, fullLoad, nil
+		return neededSchemaVersion, tblIDs, fullLoad, nil
 	}
 
 	fullLoad = true
@@ -124,14 +131,16 @@ func (do *Domain) loadInfoSchema(handle *infoschema.Handle, usedSchemaVersion in
 		return 0, nil, fullLoad, errors.Trace(err)
 	}
 
-	newISBuilder, err := infoschema.NewBuilder(handle).InitWithDBInfos(schemas, latestSchemaVersion)
+	newISBuilder, err := infoschema.NewBuilder(handle).InitWithDBInfos(schemas, neededSchemaVersion)
 	if err != nil {
 		return 0, nil, fullLoad, errors.Trace(err)
 	}
-	logutil.Logger(context.Background()).Info("full load InfoSchema success", zap.Int64("usedSchemaVersion", usedSchemaVersion),
-		zap.Int64("latestSchemaVersion", latestSchemaVersion), zap.Duration("start time", time.Since(startTime)))
+	logutil.Logger(context.Background()).Info("full load InfoSchema success",
+		zap.Int64("usedSchemaVersion", usedSchemaVersion),
+		zap.Int64("neededSchemaVersion", neededSchemaVersion),
+		zap.Duration("start time", time.Since(startTime)))
 	newISBuilder.Build()
-	return latestSchemaVersion, nil, fullLoad, nil
+	return neededSchemaVersion, nil, fullLoad, nil
 }
 
 func (do *Domain) fetchAllSchemasWithTables(m *meta.Meta) ([]*model.DBInfo, error) {
@@ -303,7 +312,7 @@ func (do *Domain) Reload() error {
 	startTime := time.Now()
 
 	var err error
-	var latestSchemaVersion int64
+	var neededSchemaVersion int64
 
 	ver, err := do.store.CurrentVersion()
 	if err != nil {
@@ -320,7 +329,7 @@ func (do *Domain) Reload() error {
 		fullLoad        bool
 		changedTableIDs []int64
 	)
-	latestSchemaVersion, changedTableIDs, fullLoad, err = do.loadInfoSchema(do.infoHandle, schemaVersion, ver.Ver)
+	neededSchemaVersion, changedTableIDs, fullLoad, err = do.loadInfoSchema(do.infoHandle, schemaVersion, ver.Ver)
 	metrics.LoadSchemaDuration.Observe(time.Since(startTime).Seconds())
 	if err != nil {
 		metrics.LoadSchemaCounter.WithLabelValues("failed").Inc()
@@ -332,7 +341,7 @@ func (do *Domain) Reload() error {
 		logutil.Logger(context.Background()).Info("full load and reset schema validator")
 		do.SchemaValidator.Reset()
 	}
-	do.SchemaValidator.Update(ver.Ver, schemaVersion, latestSchemaVersion, changedTableIDs)
+	do.SchemaValidator.Update(ver.Ver, schemaVersion, neededSchemaVersion, changedTableIDs)
 
 	lease := do.DDL().GetLease()
 	sub := time.Since(startTime)

domain/domain_test.go

@@ -14,6 +14,7 @@
 package domain
 
 import (
+	"context"
 	"testing"
 	"time"
 
@@ -78,10 +79,21 @@ func (*testSuite) TestT(c *C) {
 	// for setting lease
 	lease := 100 * time.Millisecond
 
-	// for GetSnapshotInfoSchema
-	snapIs, err := dom.GetSnapshotInfoSchema(snapTS)
+	// for updating the self schema version
+	goCtx, cancel := context.WithTimeout(context.Background(), 10*time.Millisecond)
+	err = dd.SchemaSyncer().OwnerCheckAllVersions(goCtx, is.SchemaMetaVersion())
+	cancel()
 	c.Assert(err, IsNil)
+	snapIs, err := dom.GetSnapshotInfoSchema(snapTS)
 	c.Assert(snapIs, NotNil)
+	c.Assert(err, IsNil)
+	// Make sure that the self schema version doesn't be changed.
+	goCtx, cancel = context.WithTimeout(context.Background(), 10*time.Millisecond)
+	err = dd.SchemaSyncer().OwnerCheckAllVersions(goCtx, is.SchemaMetaVersion())
+	cancel()
+	c.Assert(err, IsNil)
+
+	// for GetSnapshotInfoSchema
 	snapTS = oracle.EncodeTSO(oracle.GetPhysical(time.Now()))
 	snapIs, err = dom.GetSnapshotInfoSchema(snapTS)
 	c.Assert(err, IsNil)