txn: support shared lock

integration_tests/2pc_test.go

@@ -88,7 +88,8 @@ func (s *testCommitterSuite) SetupSuite() {
 
 func (s *testCommitterSuite) TearDownSuite() {
 	s.Nil(failpoint.Disable("tikvclient/injectLiveness"))
-	atomic.StoreUint64(&transaction.CommitMaxBackoff, 20000)
+	atomic.StoreUint64(&transaction.ManagedLockTTL, 20000)
+	atomic.StoreUint64(&transaction.CommitMaxBackoff, 40000)
 }
 
 func (s *testCommitterSuite) SetupTest() {

integration_tests/pipelined_memdb_test.go

@@ -475,6 +475,7 @@ func (s *testPipelinedMemDBSuite) TestPipelinedDMLFailedByPKRollback() {
 func (s *testPipelinedMemDBSuite) TestPipelinedDMLFailedByPKMaxTTLExceeded() {
 	originManagedTTLVal := atomic.LoadUint64(&transaction.ManagedLockTTL)
 	originMaxPipelinedTxnTTL := atomic.LoadUint64(&transaction.MaxPipelinedTxnTTL)
+	restoreConf := restoreGlobalConfFunc()                   // Get the restore function BEFORE changing config
 	atomic.StoreUint64(&transaction.ManagedLockTTL, 100)     // set to 100ms
 	atomic.StoreUint64(&transaction.MaxPipelinedTxnTTL, 200) // set to 200ms
 	updateGlobalConfig(func(conf *config.Config) {
@@ -483,7 +484,7 @@ func (s *testPipelinedMemDBSuite) TestPipelinedDMLFailedByPKMaxTTLExceeded() {
 	defer func() {
 		atomic.StoreUint64(&transaction.ManagedLockTTL, originManagedTTLVal)
 		atomic.StoreUint64(&transaction.MaxPipelinedTxnTTL, originMaxPipelinedTxnTTL)
-		restoreGlobalConfFunc()
+		restoreConf()
 	}()
 
 	txn, err := s.store.Begin(tikv.WithDefaultPipelinedTxn())