diff --git a/dbms/include/DB/Storages/MergeTree/MergeTreeWhereOptimizer.h b/dbms/include/DB/Storages/MergeTree/MergeTreeWhereOptimizer.h
index 15c2627ca19120d3257dfdeac328a0b9abc3e1ed..fef34a28ddc5fca8b3b1c9fe36b6c6892244194e 100644
--- a/dbms/include/DB/Storages/MergeTree/MergeTreeWhereOptimizer.h
+++ b/dbms/include/DB/Storages/MergeTree/MergeTreeWhereOptimizer.h
@@ -38,7 +38,7 @@ public:
 
 	MergeTreeWhereOptimizer(
 		ASTPtr & query, const Context & context, const MergeTreeData & data, const Names & column_names,
-		Logger * log);
+		Poco::Logger * log);
 
 private:
 	void optimize(ASTSelectQuery & select) const;