diff --git a/dbms/src/Interpreters/Settings.h b/dbms/src/Interpreters/Settings.h
index 20e07d15916..3121389a6db 100644
--- a/dbms/src/Interpreters/Settings.h
+++ b/dbms/src/Interpreters/Settings.h
@@ -41,6 +41,7 @@ struct Settings
     M(SettingUInt64, min_insert_block_size_rows, DEFAULT_INSERT_BLOCK_SIZE, "Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough.") \
     M(SettingUInt64, min_insert_block_size_bytes, (DEFAULT_INSERT_BLOCK_SIZE * 256), "Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough.") \
     M(SettingMaxThreads, max_threads, 0, "The maximum number of threads to execute the request. By default, it is determined automatically.") \
+    M(SettingMaxAlterThreads, max_alter_threads, 0, "The maximum number of threads to execute the ALTER requests. By default, it is determined automatically.") \
     M(SettingUInt64, max_read_buffer_size, DBMS_DEFAULT_BUFFER_SIZE, "The maximum size of the buffer to read from the filesystem.") \
     M(SettingUInt64, max_distributed_connections, 1024, "The maximum number of connections for distributed processing of one query (should be greater than max_threads).") \
     M(SettingUInt64, max_query_size, 262144, "Which part of the query can be read into RAM for parsing (the remaining data for INSERT, if any, is read later)") \
diff --git a/dbms/src/Interpreters/SettingsCommon.h b/dbms/src/Interpreters/SettingsCommon.h
index ff2c0cd9339..abe6e052fbc 100644
--- a/dbms/src/Interpreters/SettingsCommon.h
+++ b/dbms/src/Interpreters/SettingsCommon.h
@@ -87,6 +87,12 @@ struct SettingMaxThreads
     UInt64 getAutoValueImpl() const;
 };
 
+struct SettingMaxAlterThreads: public SettingMaxThreads
+{
+    SettingMaxAlterThreads(UInt64 x = 0):
+        SettingMaxThreads(x)
+    {}
+};
 
 struct SettingSeconds
 {
diff --git a/dbms/src/Storages/StorageMergeTree.cpp b/dbms/src/Storages/StorageMergeTree.cpp
index a7a618873a8..620afcb0f91 100644
--- a/dbms/src/Storages/StorageMergeTree.cpp
+++ b/dbms/src/Storages/StorageMergeTree.cpp
@@ -194,15 +194,17 @@ void StorageMergeTree::rename(const String & new_path_to_db, const String & /*ne
 
 
 std::vector<MergeTreeData::AlterDataPartTransactionPtr> StorageMergeTree::prepare_alter_transactions(
-    const ColumnsDescription& new_columns, const IndicesDescription& new_indices, const size_t thread_pool_size)
+    const ColumnsDescription& new_columns, const IndicesDescription& new_indices, const Context & context)
 {
-    ThreadPool thread_pool(thread_pool_size);
-
     auto parts = data.getDataParts({MergeTreeDataPartState::PreCommitted, MergeTreeDataPartState::Committed, MergeTreeDataPartState::Outdated});
     std::vector<MergeTreeData::AlterDataPartTransactionPtr> transactions(parts.size());
 
     const auto& columns_for_parts = new_columns.getAllPhysical();
 
+    const Settings & settings = context.getSettingsRef();
+    size_t thread_pool_size = std::min<size_t>(parts.size(), settings.max_alter_threads);
+    ThreadPool thread_pool(thread_pool_size);
+
     size_t i = 0;
     for (const auto & part : parts)
     {
@@ -259,7 +261,7 @@ void StorageMergeTree::alter(
     ASTPtr new_primary_key_ast = data.primary_key_ast;
     params.apply(new_columns, new_indices, new_order_by_ast, new_primary_key_ast);
 
-    auto transactions = prepare_alter_transactions(new_columns, new_indices, 2 * getNumberOfPhysicalCPUCores());
+    auto transactions = prepare_alter_transactions(new_columns, new_indices, context);
 
     auto table_hard_lock = lockStructureForAlter(context.getCurrentQueryId());
 
diff --git a/dbms/src/Storages/StorageMergeTree.h b/dbms/src/Storages/StorageMergeTree.h
index 36b6cb9fc36..0f34c71213c 100644
--- a/dbms/src/Storages/StorageMergeTree.h
+++ b/dbms/src/Storages/StorageMergeTree.h
@@ -133,7 +133,7 @@ private:
     BackgroundProcessingPool::TaskHandle background_task_handle;
 
     std::vector<MergeTreeData::AlterDataPartTransactionPtr> prepare_alter_transactions(
-        const ColumnsDescription& new_columns, const IndicesDescription& new_indices, const size_t thread_pool_size);
+        const ColumnsDescription& new_columns, const IndicesDescription& new_indices, const Context & context);
 
     void loadMutations();