Flaky test debugging

go/mysql/flavor_mysql.go

@@ -275,7 +275,7 @@ func (mysqlFlavor) waitUntilPositionCommand(ctx context.Context, pos Position) (
 		}
 	}
 
-	return fmt.Sprintf("SELECT WAIT_FOR_EXECUTED_GTID_SET('%s', %v)", pos, timeoutSeconds), nil
+	return fmt.Sprintf("SELECT WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS('%s', %v)", pos, timeoutSeconds), nil
 }
 
 // readBinlogEvent is part of the Flavor interface.

go/test/endtoend/cluster/mysqlctld_process.go

@@ -23,8 +23,11 @@ import (
 	"os/exec"
 	"path"
 	"strings"
+	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"vitess.io/vitess/go/mysql"
 	"vitess.io/vitess/go/vt/log"
 )
@@ -150,6 +153,42 @@ func (mysqlctld *MysqlctldProcess) CleanupFiles(tabletUID int) {
 	os.RemoveAll(path.Join(os.Getenv("VTDATAROOT"), fmt.Sprintf("/vt_%010d", tabletUID)))
 }
 
+func PrintFiles(t *testing.T, tabletUID int, files ...string) {
+	dir := path.Join(os.Getenv("VTDATAROOT"), fmt.Sprintf("/vt_%010d", tabletUID))
+	var directories []string
+	directories = append(directories, dir)
+
+	for len(directories) > 0 {
+		dir = directories[0]
+		directories = directories[1:]
+		entries, err := os.ReadDir(dir)
+		require.NoError(t, err)
+		for _, entry := range entries {
+			name := path.Join(dir, entry.Name())
+			if entry.IsDir() {
+				directories = append(directories, name)
+				continue
+			}
+			if len(files) != 0 {
+				fileFound := false
+				for _, file := range files {
+					if strings.EqualFold(entry.Name(), file) {
+						fileFound = true
+						break
+					}
+				}
+				if !fileFound {
+					continue
+				}
+			}
+			res, err := os.ReadFile(name)
+			require.NoError(t, err)
+			log.Errorf("READING FILE - %v", name)
+			log.Errorf("%v", string(res))
+		}
+	}
+}
+
 // MysqlCtldProcessInstance returns a Mysqlctld handle for mysqlctld process
 // configured with the given Config.
 func MysqlCtldProcessInstance(tabletUID int, mySQLPort int, tmpDirectory string) *MysqlctldProcess {

go/test/endtoend/mysqlctld/mysqlctld_test.go

@@ -133,6 +133,7 @@ func TestRestart(t *testing.T) {
 	defer cluster.PanicHandler(t)
 	err := primaryTablet.MysqlctldProcess.Stop()
 	require.Nil(t, err)
+	cluster.PrintFiles(t, primaryTablet.TabletUID, "error.log")
 	primaryTablet.MysqlctldProcess.CleanupFiles(primaryTablet.TabletUID)
 	err = primaryTablet.MysqlctldProcess.Start()
 	require.Nil(t, err)