Fix mutation of StorageMemory

fix

fix

src/Storages/StorageMemory.cpp

@@ -262,7 +262,14 @@ void StorageMemory::mutate(const MutationCommands & commands, ContextPtr context
     auto metadata_snapshot = getInMemoryMetadataPtr();
     auto storage = getStorageID();
     auto storage_ptr = DatabaseCatalog::instance().getTable(storage, context);
-    auto interpreter = std::make_unique<MutationsInterpreter>(storage_ptr, metadata_snapshot, commands, context, true);
+
+    /// When max_threads > 1, the order of returning blocks is uncentain,
+    /// which will lead to inconsistency after updateBlockData.
+    auto new_context = Context::createCopy(context);
+    new_context->setSetting("max_streams_to_max_threads_ratio", 1);
+    new_context->setSetting("max_threads", 1);
+
+    auto interpreter = std::make_unique<MutationsInterpreter>(storage_ptr, metadata_snapshot, commands, new_context, true);
     auto in = interpreter->execute();
 
     in->readPrefix();

tests/queries/0_stateless/01867_fix_storage_memory_mutation.sql

@@ -0,0 +1,32 @@
+DROP TABLE IF EXISTS mem_test;
+
+CREATE TABLE mem_test
+(
+    `a` Int64,
+    `b` Int64
+)
+ENGINE = Memory;
+
+SET max_block_size = 3;
+
+INSERT INTO mem_test SELECT
+    number,
+    number
+FROM numbers(100);
+
+ALTER TABLE mem_test
+    UPDATE a = 0 WHERE b = 99;
+ALTER TABLE mem_test
+    UPDATE a = 0 WHERE b = 99;
+ALTER TABLE mem_test
+    UPDATE a = 0 WHERE b = 99;
+ALTER TABLE mem_test
+    UPDATE a = 0 WHERE b = 99;
+ALTER TABLE mem_test
+    UPDATE a = 0 WHERE b = 99;
+
+SELECT *
+FROM mem_test
+FORMAT Null;
+
+DROP TABLE mem_test;