Implementation of mysql-connection_max_age_ms

If a connection has a lifetime greated than mysql-connection_max_age_ms , it is dropped

See #563

include/MySQL_Thread.h

@@ -266,6 +266,7 @@ class MySQL_Threads_Handler
 		int shun_recovery_time_sec;
 		int connect_retries_on_failure;
 		int connect_retries_delay;
+		int connection_max_age_ms;
 		int connect_timeout_server;
 		int connect_timeout_server_max;
 		int free_connections_pct;

include/mysql_connection.h

@@ -48,6 +48,7 @@ class MySQL_Connection {
 		char *ptr;
 	} query;
 	char scramble_buff[40];
+	unsigned long long creation_time;
 	unsigned long long last_time_used;
 	unsigned long long timeout;
 	int fd;

include/proxysql_structs.h

@@ -705,6 +705,7 @@ __thread int mysql_thread___shun_on_failures;
 __thread int mysql_thread___shun_recovery_time_sec;
 __thread int mysql_thread___connect_retries_on_failure;
 __thread int mysql_thread___connect_retries_delay;
+__thread int mysql_thread___connection_max_age_ms;
 __thread int mysql_thread___connect_timeout_server;
 __thread int mysql_thread___connect_timeout_server_max;
 __thread uint16_t mysql_thread___server_capabilities;
@@ -771,6 +772,7 @@ extern __thread int mysql_thread___shun_on_failures;
 extern __thread int mysql_thread___shun_recovery_time_sec;
 extern __thread int mysql_thread___connect_retries_on_failure;
 extern __thread int mysql_thread___connect_retries_delay;
+extern __thread int mysql_thread___connection_max_age_ms;
 extern __thread int mysql_thread___connect_timeout_server;
 extern __thread int mysql_thread___connect_timeout_server_max;
 extern __thread uint16_t mysql_thread___server_capabilities;

lib/MySQL_HostGroups_Manager.cpp

@@ -855,6 +855,21 @@ void MySQL_HostGroups_Manager::drop_all_idle_connections() {
 				delete mc;
 				//__sync_fetch_and_sub(&status.server_connections_connected, 1);
 			}
+
+			// drop all connections with life exceeding mysql-connection_max_age
+			if (mysql_thread___connection_max_age_ms) {
+				unsigned long long curtime=monotonic_time();
+				int i=0;
+				for (i=0; i<(int)pa->len ; i++) {
+					MySQL_Connection *mc=(MySQL_Connection *)pa->index(i);
+					if (curtime > mc->creation_time + mysql_thread___connection_max_age_ms * 1000) {
+						mc=(MySQL_Connection *)pa->remove_index_fast(0);
+						delete mc;
+						i--;
+					}
+				}
+			}
+
 		}
 	}
 }

lib/MySQL_Thread.cpp

@@ -139,6 +139,7 @@ static char * mysql_thread_variables_names[]= {
 	(char *)"shun_recovery_time_sec",
 	(char *)"connect_retries_on_failure",
 	(char *)"connect_retries_delay",
+	(char *)"connection_max_age_ms",
 	(char *)"connect_timeout_server",
 	(char *)"connect_timeout_server_max",
 	(char *)"eventslog_filename",
@@ -214,6 +215,7 @@ MySQL_Threads_Handler::MySQL_Threads_Handler() {
 	variables.shun_on_failures=5;
 	variables.shun_recovery_time_sec=10;
 	variables.connect_retries_on_failure=5;
+	variables.connection_max_age_ms=0;
 	variables.connect_timeout_server=1000;
 	variables.connect_timeout_server_max=10000;
 	variables.free_connections_pct=10;
@@ -392,6 +394,7 @@ int MySQL_Threads_Handler::get_variable_int(char *name) {
 	if (!strcasecmp(name,"shun_on_failures")) return (int)variables.shun_on_failures;
 	if (!strcasecmp(name,"shun_recovery_time_sec")) return (int)variables.shun_recovery_time_sec;
 	if (!strcasecmp(name,"connect_retries_on_failure")) return (int)variables.connect_retries_on_failure;
+	if (!strcasecmp(name,"connection_max_age_ms")) return (int)variables.connection_max_age_ms;
 	if (!strcasecmp(name,"connect_timeout_server")) return (int)variables.connect_timeout_server;
 	if (!strcasecmp(name,"connect_timeout_server_max")) return (int)variables.connect_timeout_server_max;
 	if (!strcasecmp(name,"connect_retries_delay")) return (int)variables.connect_retries_delay;
@@ -516,6 +519,10 @@ char * MySQL_Threads_Handler::get_variable(char *name) {	// this is the public f
 		sprintf(intbuf,"%d",variables.connect_retries_on_failure);
 		return strdup(intbuf);
 	}
+	if (!strcasecmp(name,"connection_max_age_ms")) {
+		sprintf(intbuf,"%d",variables.connection_max_age_ms);
+		return strdup(intbuf);
+	}
 	if (!strcasecmp(name,"connect_timeout_server")) {
 		sprintf(intbuf,"%d",variables.connect_timeout_server);
 		return strdup(intbuf);
@@ -936,6 +943,15 @@ bool MySQL_Threads_Handler::set_variable(char *name, char *value) {	// this is t
 			return false;
 		}
 	}
+	if (!strcasecmp(name,"connection_max_age_ms")) {
+		int intv=atoi(value);
+		if (intv >= 0 && intv <= 3600*24*1000) {
+			variables.connection_max_age_ms=intv;
+			return true;
+		} else {
+			return false;
+		}
+	}
 	if (!strcasecmp(name,"connect_timeout_server")) {
 		int intv=atoi(value);
 		if (intv >= 10 && intv <= 120*1000) {
@@ -1792,6 +1808,7 @@ void MySQL_Thread::refresh_variables() {
 	mysql_thread___shun_on_failures=GloMTH->get_variable_int((char *)"shun_on_failures");
 	mysql_thread___shun_recovery_time_sec=GloMTH->get_variable_int((char *)"shun_recovery_time_sec");
 	mysql_thread___connect_retries_on_failure=GloMTH->get_variable_int((char *)"connect_retries_on_failure");
+	mysql_thread___connection_max_age_ms=GloMTH->get_variable_int((char *)"connection_max_age_ms");
 	mysql_thread___connect_timeout_server=GloMTH->get_variable_int((char *)"connect_timeout_server");
 	mysql_thread___connect_timeout_server_max=GloMTH->get_variable_int((char *)"connect_timeout_server_max");
 	mysql_thread___free_connections_pct=GloMTH->get_variable_int((char *)"free_connections_pct");

lib/mysql_connection.cpp

@@ -159,6 +159,7 @@ MySQL_Connection::MySQL_Connection() {
 	query.length=0;
 	largest_query_length=0;
 	MyRS=NULL;
+	creation_time=0;
 	proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 4, "Creating new MySQL_Connection %p\n", this);
 };
 
@@ -765,6 +766,7 @@ int MySQL_Connection::async_connect(short event) {
 	if (async_state_machine==ASYNC_CONNECT_SUCCESSFUL) {
 		async_state_machine=ASYNC_IDLE;
 		myds->wait_until=0;
+		creation_time=myds->sess->thread->curtime;
 		return 0;
 	}
 	handler(event);

lib/mysql_data_stream.cpp

@@ -939,10 +939,14 @@ void MySQL_Data_Stream::setDSS_STATE_QUERY_SENT_NET() {
 void MySQL_Data_Stream::return_MySQL_Connection_To_Pool() {
 	MySQL_Connection *mc=myconn;
 	mc->last_time_used=sess->thread->curtime;
-	detach_connection();
-	unplug_backend();
-	//mc->async_state_machine=ASYNC_IDLE;
-	MyHGM->push_MyConn_to_pool(mc);
+	if ((mysql_thread___connection_max_age_ms) && (mc->last_time_used > mc->creation_time + mysql_thread___connection_max_age_ms * 1000)) {
+		destroy_MySQL_Connection_From_Pool(true);
+	} else {
+		detach_connection();
+		unplug_backend();
+		//mc->async_state_machine=ASYNC_IDLE;
+		MyHGM->push_MyConn_to_pool(mc);
+	}
 }
 
 void MySQL_Data_Stream::free_mysql_real_query() {