incremental backup is always using 'builtin' engine

Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>

go/vt/mysqlctl/backup.go

@@ -135,16 +135,24 @@ func Backup(ctx context.Context, params BackupParams) error {
 		return vterrors.Wrap(err, "StartBackup failed")
 	}
 
-	be, err := GetBackupEngine()
-	if err != nil {
-		return vterrors.Wrap(err, "failed to find backup engine")
-	}
 	// Scope stats to selected backup engine.
 	beParams := params.Copy()
 	beParams.Stats = params.Stats.Scope(
 		stats.Component(stats.BackupEngine),
 		stats.Implementation(titleCase(backupEngineImplementation)),
 	)
+	var be BackupEngine
+	if isIncrementalBackup(beParams) {
+		// Incremental backups are always done via 'builtin' engine, which copies
+		// appropriate binlog files.
+		be = BackupRestoreEngineMap[builtinBackupEngineName]
+	} else {
+		be, err = GetBackupEngine()
+		if err != nil {
+			return vterrors.Wrap(err, "failed to find backup engine")
+		}
+	}
+
 	// Take the backup, and either AbortBackup or EndBackup.
 	usable, err := be.ExecuteBackup(ctx, beParams, bh)
 	logger := params.Logger

go/vt/mysqlctl/backupengine.go

@@ -167,6 +167,11 @@ func init() {
 	}
 }
 
+// isIncrementalBackup is a convenience function to check whether the params indicate an incremental backup request
+func isIncrementalBackup(params BackupParams) bool {
+	return params.IncrementalFromPos != ""
+}
+
 func registerBackupEngineFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&backupEngineImplementation, "backup_engine_implementation", backupEngineImplementation, "Specifies which implementation to use for creating new backups (builtin or xtrabackup). Restores will always be done with whichever engine created a given backup.")
 }

go/vt/mysqlctl/builtinbackupengine.go

@@ -153,11 +153,6 @@ func registerBuiltinBackupEngineFlags(fs *pflag.FlagSet) {
 	fs.UintVar(&builtinBackupFileWriteBufferSize, "builtinbackup-file-write-buffer-size", builtinBackupFileWriteBufferSize, "write files using an IO buffer of this many bytes. Golang defaults are used when set to 0.")
 }
 
-// isIncrementalBackup is a convenience function to check whether the params indicate an incremental backup request
-func isIncrementalBackup(params BackupParams) bool {
-	return params.IncrementalFromPos != ""
-}
-
 // fullPath returns the full path of the entry, based on its type
 func (fe *FileEntry) fullPath(cnf *Mycnf) (string, error) {
 	// find the root to use
@@ -1126,5 +1121,5 @@ func getPrimaryPosition(ctx context.Context, tmc tmclient.TabletManagerClient, t
 }
 
 func init() {
-	BackupRestoreEngineMap["builtin"] = &BuiltinBackupEngine{}
+	BackupRestoreEngineMap[builtinBackupEngineName] = &BuiltinBackupEngine{}
 }

go/vt/mysqlctl/xtrabackupengine.go

@@ -167,9 +167,18 @@ func closeFile(wc io.WriteCloser, fileName string, logger logutil.Logger, finalE
 	}
 }
 
-// ExecuteBackup returns a boolean that indicates if the backup is usable,
+// ExecuteBackup runs a backup based on given params. This could be a full or incremental backup.
+// The function returns a boolean that indicates if the backup is usable, and an overall error.
+func (be *XtrabackupEngine) ExecuteBackup(ctx context.Context, params BackupParams, bh backupstorage.BackupHandle) (bool, error) {
+	params.Logger.Infof("Executing Backup at %v for keyspace/shard %v/%v on tablet %v, concurrency: %v, compress: %v, incrementalFromPos: %v",
+		params.BackupTime, params.Keyspace, params.Shard, params.TabletAlias, params.Concurrency, backupStorageCompress, params.IncrementalFromPos)
+
+	return be.executeFullBackup(ctx, params, bh)
+}
+
+// executeFullBackup returns a boolean that indicates if the backup is usable,
 // and an overall error.
-func (be *XtrabackupEngine) ExecuteBackup(ctx context.Context, params BackupParams, bh backupstorage.BackupHandle) (complete bool, finalErr error) {
+func (be *XtrabackupEngine) executeFullBackup(ctx context.Context, params BackupParams, bh backupstorage.BackupHandle) (complete bool, finalErr error) {
 
 	if params.IncrementalFromPos != "" {
 		return false, vterrors.New(vtrpc.Code_INVALID_ARGUMENT, "incremental backups not supported in xtrabackup engine.")