Issue #121

Calls from Standard_ProxySQL_Admin to MySQL_Threads_Handler are wrapped by lock
LOAD MYSQL VARIABLES TO RUNTIME (or equivalent) calls commit() so that other threads will update

include/mysql_thread.h

@@ -258,6 +258,7 @@ class MySQL_Threads_Handler
 	virtual void shutdown_threads() {};
 	virtual void wrlock() {};
   virtual void wrunlock() {};
+	virtual void commit() {};
 	virtual char *get_variable(char *name) {return NULL;};
 	virtual bool set_variable(char *name, char *value) {return false;};
 	virtual char **get_variables_list() {return NULL;}

lib/Standard_MySQL_Thread.cpp

@@ -220,6 +220,12 @@ class Standard_MySQL_Threads_Handler: public MySQL_Threads_Handler
 	virtual void wrunlock() {                                                                                                           
 		spin_wrunlock(&rwlock);                                                                                                                              
 	}
+
+	virtual void commit() {
+	__sync_add_and_fetch(&__global_MySQL_Thread_Variables_version,1);
+	proxy_debug(PROXY_DEBUG_MYSQL_SERVER, 1, "Increasing version number to %d - all threads will notice this and refresh their variables\n", __global_MySQL_Thread_Variables_version);
+	};
+
 	char *get_variable_string(char *name) {
 		if (!strcmp(name,"server_version")) return strdup(variables.server_version);
 		if (!strcmp(name,"default_schema")) return strdup(variables.default_schema);

lib/Standard_ProxySQL_Admin.cpp

@@ -708,6 +708,7 @@ void *child_mysql(void *arg) {
 	int client = *(int *)arg;
 	__thr_sfp=l_mem_init();
 
+	GloMTH->wrlock();
 	mysql_thread___server_version=GloMTH->get_variable((char *)"server_version");
 	mysql_thread___default_schema=GloMTH->get_variable((char *)"default_schema");
 	{
@@ -715,6 +716,7 @@ void *child_mysql(void *arg) {
 		mysql_thread___server_capabilities=atoi(s);
 		free(s);
 	}
+	GloMTH->wrunlock();
 
 	struct pollfd fds[1];
 	nfds_t nfds=1;
@@ -1150,6 +1152,7 @@ void Standard_ProxySQL_Admin::flush_mysql_variables___database_to_runtime(SQLite
 		proxy_error("Error on %s : %s\n", q, error);
 		return;
 	} else {
+		GloMTH->wrlock();
 		for (std::vector<SQLite3_row *>::iterator it = resultset->rows.begin() ; it != resultset->rows.end(); ++it) {
 			SQLite3_row *r=*it;
 			bool rc=GloMTH->set_variable(r->fields[0],r->fields[1]);
@@ -1173,6 +1176,8 @@ void Standard_ProxySQL_Admin::flush_mysql_variables___database_to_runtime(SQLite
 				proxy_debug(PROXY_DEBUG_ADMIN, 4, "Set variable %s with value \"%s\"\n", r->fields[0],r->fields[1]);
 			}
 		}
+		GloMTH->commit();
+		GloMTH->wrunlock();
 	}
 	if (resultset) delete resultset;
 }
@@ -1213,15 +1218,16 @@ void Standard_ProxySQL_Admin::flush_mysql_variables___runtime_to_database(SQLite
     a=(char *)"INSERT OR IGNORE INTO global_variables(variable_name, variable_value) VALUES(\"mysql-%s\",\"%s\")";
   }
   int l=strlen(a)+200;
+	GloMTH->wrlock();
 	char **varnames=GloMTH->get_variables_list();	
-	// FIXME: add lock
   char *query=(char *)malloc(l);
 	for (int i=0; varnames[i]; i++) {
 		char *val=GloMTH->get_variable(varnames[i]);
 		sprintf(query, a, varnames[i], val);
 		db->execute(query);
 		free(val);
-	}	
+	}
+	GloMTH->wrunlock();
 	free(query);
 	for (int i=0; varnames[i]; i++) {
 		free(varnames[i]);