diff --git a/dbms/include/DB/Dictionaries/ClickhouseDictionarySource.h b/dbms/include/DB/Dictionaries/ClickhouseDictionarySource.h
index a74092ef20b..48c05e63c36 100644
--- a/dbms/include/DB/Dictionaries/ClickhouseDictionarySource.h
+++ b/dbms/include/DB/Dictionaries/ClickhouseDictionarySource.h
@@ -28,19 +28,25 @@ public:
 		  table{config.getString(config_prefix + "table")},
 		  sample_block{sample_block}, context(context),
 		  is_local{isLocal(host, port)},
-		  pool{/*is_local ? nullptr : */ext::make_unique<ConnectionPool>(
+		  pool{is_local ? nullptr : ext::make_unique<ConnectionPool>(
 			  max_connections, host, port, db, user, password, context.getDataTypeFactory(),
 			  "ClickhouseDictionarySource")
 		  },
 		  load_all_query{composeLoadAllQuery(sample_block, table)}
-	{}
+	{
+		if (is_local)
+			throw Exception{
+				"Cannot use local clickhouse as a dictionary source",
+				ErrorCodes::LOGICAL_ERROR
+			};
+	}
 
 	ClickhouseDictionarySource(const ClickhouseDictionarySource & other)
 		: host{other.host}, port{other.port}, user{other.user}, password{other.password},
 		  db{other.db}, table{other.db},
 		  sample_block{other.sample_block}, context(other.context),
 		  is_local{other.is_local},
-		  pool{/*is_local ? nullptr : */ext::make_unique<ConnectionPool>(
+		  pool{is_local ? nullptr : ext::make_unique<ConnectionPool>(
 			  max_connections, host, port, db, user, password, context.getDataTypeFactory(),
 			  "ClickhouseDictionarySource")},
 		  load_all_query{other.load_all_query}