diff --git a/db/db_impl/db_impl_write.cc b/db/db_impl/db_impl_write.cc
index b6b6dd22d5c..dd7f65f03f7 100644
--- a/db/db_impl/db_impl_write.cc
+++ b/db/db_impl/db_impl_write.cc
@@ -2254,11 +2254,16 @@ Status DBImpl::SwitchMemtable(ColumnFamilyData* cfd, WriteContext* context) {
                                      mutable_cf_options);
 
 #ifndef ROCKSDB_LITE
-  mutex_.Unlock();
+  // From above, the memtable has been converted to imm memtable and apended to
+  // memlist. If we unlock here, it has possibility to be picked by a concurrent
+  // flush job. Furthermore, that flush job may even be completed and calls
+  // NotifyOnFlushCompleted before the following NotifyOnMemTableSealed which
+  // can cause troubles.
+  // So, unlike Facebook/Rocksdb, we does not unlock here.
+
   // Notify client that memtable is sealed, now that we have successfully
   // installed a new memtable
   NotifyOnMemTableSealed(cfd, memtable_info);
-  mutex_.Lock();
 #endif  // ROCKSDB_LITE
   // It is possible that we got here without checking the value of i_os, but
   // that is okay.  If we did, it most likely means that s was already an error.