From d680a7f8daff885a0a868aff628dac72d6d8e7ed Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Tue, 17 May 2016 04:17:32 +0300
Subject: [PATCH] Alter primary key: development [#METR-21119].

---
 dbms/include/DB/Databases/IDatabase.h  |  2 +-
 dbms/src/Storages/StorageMergeTree.cpp | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/dbms/include/DB/Databases/IDatabase.h b/dbms/include/DB/Databases/IDatabase.h
index 3d7ce82f933..9b711f3ef83 100644
--- a/dbms/include/DB/Databases/IDatabase.h
+++ b/dbms/include/DB/Databases/IDatabase.h
@@ -79,7 +79,7 @@ public:
 		const NamesAndTypesList & materialized_columns,
 		const NamesAndTypesList & alias_columns,
 		const ColumnDefaults & column_defaults,
-		const ASTModifier & engine_modifier);
+		const ASTModifier & engine_modifier) = 0;
 
 	/// Получить запрос CREATE TABLE для таблицы. Может выдавать информацию и для detached таблиц, для которых есть метаданные.
 	virtual ASTPtr getCreateQuery(const String & name) const = 0;
diff --git a/dbms/src/Storages/StorageMergeTree.cpp b/dbms/src/Storages/StorageMergeTree.cpp
index 8d41055c5a1..b4932d3bcb9 100644
--- a/dbms/src/Storages/StorageMergeTree.cpp
+++ b/dbms/src/Storages/StorageMergeTree.cpp
@@ -8,6 +8,7 @@
 #include <DB/Common/escapeForFileName.h>
 #include <DB/Interpreters/InterpreterAlterQuery.h>
 #include <DB/Interpreters/ExpressionAnalyzer.h>
+#include <DB/Parsers/ASTFunction.h>
 #include <Poco/DirectoryIterator.h>
 
 
@@ -211,7 +212,16 @@ void StorageMergeTree::alter(
 	context.getDatabase(database_name)->alterTable(
 		context, table_name,
 		new_columns, new_materialized_columns, new_alias_columns, new_column_defaults,
-		[&new_primary_key_ast] (ASTPtr & primary_key_ast) { primary_key_ast = new_primary_key_ast; });
+		[&new_primary_key_ast] (ASTPtr & engine_ast)
+		{
+			ASTFunction * tuple = new ASTFunction(new_primary_key_ast->range);
+			tuple->name = "tuple";
+			tuple->arguments = new_primary_key_ast;
+			tuple->children.push_back(tuple->arguments);
+
+			/// Первичный ключ находится на втором месте в описании движка таблицы и может быть представлен в виде кортежа.
+			typeid_cast<ASTExpressionList &>(*typeid_cast<ASTFunction &>(*engine_ast).arguments).children.at(1) = tuple;
+		});
 
 	materialized_columns = new_materialized_columns;
 	alias_columns = new_alias_columns;