diff --git a/common/dbcore.cpp b/common/dbcore.cpp
index 17cdca092..600fe11a6 100644
--- a/common/dbcore.cpp
+++ b/common/dbcore.cpp
@@ -59,7 +59,7 @@ void DBcore::ping() {
 	MDatabase.unlock();
 }
 
-bool DBcore::RunQuery(const std::string query, char* errbuf, MYSQL_RES** result, uint32* affected_rows, uint32* last_insert_id, uint32* errnum, bool retry) {
+bool DBcore::RunQuery(const std::string& query, char* errbuf, MYSQL_RES** result, uint32* affected_rows, uint32* last_insert_id, uint32* errnum, bool retry) {
 	_CP(DBcore_RunQuery);
 	if (errnum)
 		*errnum = 0;
diff --git a/common/dbcore.h b/common/dbcore.h
index 51e0ee1a4..25e33fcf2 100644
--- a/common/dbcore.h
+++ b/common/dbcore.h
@@ -22,7 +22,7 @@ public:
 	DBcore();
 	~DBcore();
 	eStatus	GetStatus() { return pStatus; }
-	bool	RunQuery(const std::string query, char* errbuf = 0, MYSQL_RES** result = 0, uint32* affected_rows = 0, uint32* last_insert_id = 0, uint32* errnum = 0, bool retry = true);
+	bool	RunQuery(const std::string& query, char* errbuf = 0, MYSQL_RES** result = 0, uint32* affected_rows = 0, uint32* last_insert_id = 0, uint32* errnum = 0, bool retry = true);
 	void	DoEscapeString(std::string& outString, const char* frombuf, uint32 fromlen);
 	void	ping();
 	MYSQL*	getMySQL(){ return &mysql; }