diff --git a/src/Storages/StorageMergeTree.cpp b/src/Storages/StorageMergeTree.cpp
index 02ea036c8ea..d14ee672727 100644
--- a/src/Storages/StorageMergeTree.cpp
+++ b/src/Storages/StorageMergeTree.cpp
@@ -141,18 +141,16 @@ void StorageMergeTree::startup()
 
 void StorageMergeTree::flush()
 {
-    if (flush_called)
+    if (flush_called.exchange(true))
         return;
 
-    flush_called = true;
     flushAllInMemoryPartsIfNeeded();
 }
 
 void StorageMergeTree::shutdown()
 {
-    if (shutdown_called)
+    if (shutdown_called.exchange(true))
         return;
-    shutdown_called = true;
 
     /// Unlock all waiting mutations
     {
diff --git a/src/Storages/StorageReplicatedMergeTree.cpp b/src/Storages/StorageReplicatedMergeTree.cpp
index a46a7c2f66f..5f829db72f8 100644
--- a/src/Storages/StorageReplicatedMergeTree.cpp
+++ b/src/Storages/StorageReplicatedMergeTree.cpp
@@ -4122,20 +4122,17 @@ void StorageReplicatedMergeTree::startup()
 
 void StorageReplicatedMergeTree::flush()
 {
-    if (flush_called)
+    if (flush_called.exchange(true))
         return;
 
-    flush_called = true;
     flushAllInMemoryPartsIfNeeded();
 }
 
 void StorageReplicatedMergeTree::shutdown()
 {
-    if (shutdown_called)
+    if (shutdown_called.exchange(true))
         return;
 
-    shutdown_called = true;
-
     /// Cancel fetches, merges and mutations to force the queue_task to finish ASAP.
     fetcher.blocker.cancelForever();
     merger_mutator.merges_blocker.cancelForever();