replica transaction: fixed tests

Signed-off-by: Andres Taylor <andres@planetscale.com>

go/test/endtoend/tabletgateway/healthcheck/vtgate_test.go

@@ -95,8 +95,7 @@ func TestReplicaTransactions(t *testing.T) {
 
 	// insert a row using master
 	exec(t, masterConn, "insert into customer(id, email) values(1,'email1')")
-
-	time.Sleep(1 * time.Second)
+	time.Sleep(1 * time.Second) // we sleep for a bit to make sure that the replication catches up
 
 	// after a short pause, SELECT the data inside a tx on a replica
 	_ = exec(t, replicaConn, "use @replica")
@@ -107,13 +106,15 @@ func TestReplicaTransactions(t *testing.T) {
 
 	// insert more data on master
 	exec(t, masterConn, "insert into customer(id, email) values(2,'email2')")
+	time.Sleep(1 * time.Second)
 
 	// replica doesn't see new row because it is in a transaction
 	qr2 := exec(t, replicaConn, "select id, email from customer")
 	assert.Equal(t, qr.Rows, qr2.Rows)
 
 	// replica should see new row after closing the transaction
 	_ = exec(t, replicaConn, "commit")
+
 	qr3 := exec(t, replicaConn, "select id, email from customer")
 	assert.Equal(t, `[[INT64(1) VARCHAR("email1")] [INT64(2) VARCHAR("email2")]]`, fmt.Sprintf("%v", qr3.Rows), "we are not seeing the updates after closing the replica transaction")
 }

go/vt/vttablet/tabletserver/tabletserver_test.go

@@ -466,8 +466,10 @@ func TestBeginOnReplica(t *testing.T) {
 	options = querypb.ExecuteOptions{
 		TransactionIsolation: querypb.ExecuteOptions_DEFAULT,
 	}
-	_, _, err = tsv.Begin(ctx, &target1, &options)
-	require.Error(t, err, "expected write tx to be refused")
+	txID, _, err = tsv.Begin(ctx, &target1, &options)
+	require.NoError(t, err, "expected write tx to be allowed")
+	err = tsv.Rollback(ctx, &target1, txID)
+	require.NoError(t, err)
 }
 
 func TestTabletServerMasterToReplica(t *testing.T) {

go/vt/vttablet/tabletserver/tx_engine.go

@@ -260,13 +260,6 @@ func (te *TxEngine) Begin(ctx context.Context, options *querypb.ExecuteOptions)
 		return 0, "", vterrors.Errorf(vtrpc.Code_UNAVAILABLE, "tx engine can't accept new transactions in state %v", te.state)
 	}
 
-	// TODO(deepthi): Can this be deleted now that we do allow replica transactions?
-	//isWriteTransaction := options == nil || options.TransactionIsolation != querypb.ExecuteOptions_CONSISTENT_SNAPSHOT_READ_ONLY
-	//if te.state == AcceptingReadOnly && isWriteTransaction {
-	//	te.stateLock.Unlock()
-	//	return 0, "", vterrors.Errorf(vtrpc.Code_UNAVAILABLE, "tx engine can only accept read-only transactions in current state")
-	//}
-
 	// By Add() to beginRequests, we block others from initiating state
 	// changes until we have finished adding this transaction
 	te.beginRequests.Add(1)