Attempted fixes for flaky tests: TestPlayerDDL and TestTabletVStreame…

…rClientVStreamRows

Signed-off-by: Rohit Nayak <[email protected]>

go/vt/vttablet/tabletmanager/vreplication/vplayer_test.go

@@ -24,6 +24,8 @@ import (
 	"testing"
 	"time"
 
+	"vitess.io/vitess/go/vt/log"
+
 	"golang.org/x/net/context"
 
 	"vitess.io/vitess/go/sqltypes"
@@ -1113,17 +1115,21 @@ func TestPlayerDDL(t *testing.T) {
 		OnDdl:    binlogdatapb.OnDDLAction_STOP,
 	}
 	cancel, id := startVReplication(t, bls, "")
+	pos0 := masterPosition(t) //For debugging only
 	execStatements(t, []string{"alter table t1 add column val varchar(128)"})
 	pos1 := masterPosition(t)
-	execStatements(t, []string{"alter table t1 drop column val"})
-	pos2 := masterPosition(t)
 	// The stop position must be the GTID of the first DDL
 	expectDBClientQueries(t, []string{
 		"begin",
 		fmt.Sprintf("/update _vt.vreplication set pos='%s'", pos1),
 		"/update _vt.vreplication set state='Stopped'",
 		"commit",
 	})
+	pos2b := masterPosition(t)
+	execStatements(t, []string{"alter table t1 drop column val"})
+	pos2 := masterPosition(t)
+	log.Errorf("Expected log:: TestPlayerDDL Positions are: before first alter %v, after first alter %v, before second alter %v, after second alter %v",
+		pos0, pos1, pos2b, pos2) //For debugging only: to check what are the positions when test works and if/when it fails
 	// Restart vreplication
 	if _, err := playerEngine.Exec(fmt.Sprintf(`update _vt.vreplication set state = 'Running', message='' where id=%d`, id)); err != nil {
 		t.Fatal(err)

go/vt/vttablet/tabletmanager/vreplication/vstreamer_client_test.go

@@ -250,13 +250,14 @@ func TestTabletVStreamerClientVStreamRows(t *testing.T) {
 
 	defer vsClient.Close(ctx)
 
-	// This asserts that events are flowing through the VStream when using mysql client
-	go vsClient.VStreamRows(ctx, "select * from t1", nil, send)
-
 	execStatements(t, []string{
 		fmt.Sprintf("insert into t1 values(1, '%s', '%s')", want, want),
 	})
 
+	// This asserts that events are flowing through VStreamRows when using mysql client
+	// This needs to happen after the insert above to avoid race where select precedes the insert
+	go vsClient.VStreamRows(ctx, "select * from t1", nil, send)
+
 	select {
 	case <-eventsChan:
 		// Success got expected