Add connection attributes for proxysql→mysql connections

lib/MySQL_Monitor.cpp

@@ -518,6 +518,7 @@ bool MySQL_Monitor_State_Data::create_new_connection() {
 		mysql_options(mysql, MYSQL_OPT_CONNECT_TIMEOUT, &timeout);
 //		mysql_options(mysql, MYSQL_OPT_READ_TIMEOUT, &timeout);
 //		mysql_options(mysql, MYSQL_OPT_WRITE_TIMEOUT, &timeout);
+		mysql_options4(mysql, MYSQL_OPT_CONNECT_ATTR_ADD, "program_name", "proxysql_monitor");
 		MYSQL *myrc=NULL;
 		if (port) {
 			myrc=mysql_real_connect(mysql, hostname, mysql_thread___monitor_username, mysql_thread___monitor_password, NULL, port, NULL, 0);

lib/MySQL_Session.cpp

@@ -41,6 +41,7 @@ static void * kill_query_thread(void *arg) {
 	KillArgs *ka=(KillArgs *)arg;
 	MYSQL *mysql;
 	mysql=mysql_init(NULL);
+	mysql_options4(mysql, MYSQL_OPT_CONNECT_ATTR_ADD, "program_name", "proxysql_killer");
 	if (!mysql) {
 		goto __exit_kill_query_thread;
 	}

lib/mysql_connection.cpp

@@ -316,6 +316,7 @@ void MySQL_Connection::connect_start() {
 	mysql=mysql_init(NULL);
 	assert(mysql);
 	mysql_options(mysql, MYSQL_OPT_NONBLOCK, 0);
+	mysql_options4(mysql, MYSQL_OPT_CONNECT_ATTR_ADD, "program_name", "proxysql");
 	if (parent->use_ssl) {
 		mysql_ssl_set(mysql, mysql_thread___ssl_p2s_key, mysql_thread___ssl_p2s_cert, mysql_thread___ssl_p2s_ca, NULL, mysql_thread___ssl_p2s_cipher);
 	}