Merge pull request #511 from sysown/498_implement_set_command

#498 implement set command

doc/global_variables.md

@@ -12,6 +12,16 @@ Also, there are 2 types of global variables, depending on which part of ProxySQL
 
 These global variables are stored in a per-thread fashion inside of the proxy in order to speed up access to them, as they are used extremely frequently. They control the behaviour of the proxy in terms of memory footprint or the number of connections accepted, and other essential aspects. Whenever a `LOAD MYSQL VARIABLES TO RUNTIME` command is issued (see the [configuration system documentation](https://github.com/sysown/proxysql-0.2/blob/master/doc/configuration_system.md) for details on that command), all the threads using the variables are notified that they have to update their values.
 
+To change the value of a global variable either use an `UPDATE` statement:
+```
+UPDATE global_variables SET variable_value=1900 WHERE variable_name='admin-refresh_interval';
+```
+or the shorter `SET` statement, similar to MySQL's:
+```
+SET admin-refresh_interval = 1700;
+SET admin-version = '1.1.1beta8';
+```
+
 Next, we're going to explain each type of variable in detail.
 
 ### `admin-admin_credentials`

doc/internal/global_variables.txt

@@ -5,6 +5,7 @@ either very simple, or managed by a simple API.
 
 Trying to make a standard API, the proposed functions are:
   virtual char **get_variables_list() {return NULL;}
+  virtual bool has_variable(char *name) {return false;}
   virtual char *get_variable(char *name) {return NULL;};
   virtual bool set_variable(char *name, char *value) {return false;};
   virtual void commit() {};
@@ -14,6 +15,8 @@ Trying to make a standard API, the proposed functions are:
 In order:
 - get_variables_list() returns an array of pointer to variables name, where the
   last element is NULL;
+- has_variable() returns true if the given name is the name of one of the module
+  variables;
 - get_variable() returns the value of a specific variable. If the variable was
   not previously set, the module should return the default value. If the
   variable doesn't exist, NULL should be returned;

include/MySQL_Thread.h

@@ -311,6 +311,7 @@ class MySQL_Threads_Handler
 	char *get_variable(char *name);
 	bool set_variable(char *name, char *value);
 	char **get_variables_list();
+	bool has_variable(const char * name);
 
 	MySQL_Threads_Handler();
 	~MySQL_Threads_Handler();

include/gen_utils.h

@@ -153,3 +153,4 @@ bool Proxy_file_exists(const char *);
 bool Proxy_file_regular(const char *);
 
 int remove_spaces(const char *);
+char *trim_spaces_in_place(char *str);

include/proxysql_admin.h

@@ -92,6 +92,7 @@ class ProxySQL_Admin {
 	bool init();
 	bool get_read_only() { return variables.admin_read_only; }
 	bool set_read_only(bool ro) { variables.admin_read_only=ro; return variables.admin_read_only; }
+	bool has_variable(const char *name);
 	void init_users();
 	void init_mysql_servers();
 	void init_mysql_query_rules();

lib/MySQL_Thread.cpp

@@ -292,7 +292,7 @@ int MySQL_Threads_Handler::listener_add(const char *iface) {
 			while(!__sync_bool_compare_and_swap(&thr->mypolls.pending_listener_add,0,rc)) {
 				usleep(100); // pause a bit
 			}
-/*		
+/*
 			while(!__sync_bool_compare_and_swap(&thr->mypolls.pending_listener_change,0,1)) { cpu_relax_pa(); }
 			while(__sync_fetch_and_add(&thr->mypolls.pending_listener_change,0)==1) { cpu_relax_pa(); }
 //			spin_wrlock(&thr->thread_mutex);
@@ -323,7 +323,7 @@ int MySQL_Threads_Handler::listener_del(const char *iface) {
 		shutdown(fd,SHUT_RDWR);
 		close(fd);
 	}
-	
+
 	return 0;
 }
 
@@ -618,7 +618,7 @@ char * MySQL_Threads_Handler::get_variable(char *name) {	// this is the public f
 		return strdup((variables.default_reconnect ? "true" : "false"));
 	}
 	return NULL;
-}	
+}
 
 
 
@@ -630,7 +630,7 @@ bool MySQL_Threads_Handler::set_variable(char *name, char *value) {	// this is t
 	// OUT:
 	// false: unable to change the variable value, either because doesn't exist, or because out of range, or read only
 	// true: variable value changed
-	// 
+	//
 	if (!value) return false;
 	size_t vallen=strlen(value);
 
@@ -1175,6 +1175,18 @@ char ** MySQL_Threads_Handler::get_variables_list() {
 	return ret;
 }
 
+// Returns true if the given name is the name of an existing mysql variable
+bool MySQL_Threads_Handler::has_variable(const char *name) {
+	size_t no_vars = sizeof(mysql_thread_variables_names) / sizeof(char *);
+	for (unsigned int i = 0; i < no_vars, mysql_thread_variables_names[i] != NULL; ++i) {
+		size_t var_len = strlen(mysql_thread_variables_names[i]);
+		if (strlen(name) == var_len && !strncmp(name, mysql_thread_variables_names[i], var_len)) {
+			return true;
+		}
+	}
+	return false;
+}
+
 void MySQL_Threads_Handler::print_version() {
 	fprintf(stderr,"Standard MySQL Threads Handler rev. %s -- %s -- %s\n", MYSQL_THREAD_VERSION, __FILE__, __TIMESTAMP__);
 }
@@ -1345,8 +1357,8 @@ void MySQL_Thread::poll_listener_add(int sock) {
 	listener_DS->fd=sock;
 
 	proxy_debug(PROXY_DEBUG_NET,1,"Created listener %p for socket %d\n", listener_DS, sock);
-	//mypoll_add(&mypolls, POLLIN, sock, listener_DS);	
-	mypolls.add(POLLIN, sock, listener_DS, monotonic_time());	
+	//mypoll_add(&mypolls, POLLIN, sock, listener_DS);
+	mypolls.add(POLLIN, sock, listener_DS, monotonic_time());
 }
 
 void MySQL_Thread::poll_listener_del(int sock) {
@@ -1489,7 +1501,7 @@ void MySQL_Thread::run() {
 			proxy_debug(PROXY_DEBUG_NET,1,"Poll for DataStream=%p will be called with FD=%d and events=%d\n", mypolls.myds[n], mypolls.fds[n].fd, mypolls.fds[n].events);
 		}
 
-	
+
 		spin_wrunlock(&thread_mutex);
 
 		while ((n=__sync_add_and_fetch(&mypolls.pending_listener_add,0))) {	// spin here
@@ -1498,7 +1510,7 @@ void MySQL_Thread::run() {
 //			if (n==1) {
 //				__sync_add_and_fetch(&mypolls.pending_listener_change,1);
 //			}
-		}	
+		}
 
 		if (mysql_thread___wait_timeout==0) {
 			// we should be going into PAUSE mode
@@ -1528,7 +1540,7 @@ void MySQL_Thread::run() {
 
 		spin_wrlock(&thread_mutex);
 		mypolls.poll_timeout=0; // always reset this to 0 . If a session needs a specific timeout, it will set this one
-		
+
 		curtime=monotonic_time();
 		if (curtime > last_maintenance_time + 200000) { // hardcoded value for now
 			last_maintenance_time=curtime;
@@ -1646,15 +1658,15 @@ void MySQL_Thread::process_data_on_data_stream(MySQL_Data_Stream *myds, unsigned
 						myds->myconn->handler(mypolls.fds[n].revents);
 					}
 				}
-				if ( (mypolls.fds[n].events & POLLOUT) 
+				if ( (mypolls.fds[n].events & POLLOUT)
 						&&
 						( (mypolls.fds[n].revents & POLLERR) || (mypolls.fds[n].revents & POLLHUP) )
 				) {
 					myds->set_net_failure();
 				}
 
 				myds->check_data_flow();
-				
+
 
 	      if (myds->active==FALSE) {
 					if (myds->sess->client_myds==myds) {