Added variable autocommit_false_is_transaction #1256

If autocommit_false_is_transaction=true (false by default), a connection
with autocommit=0 is treated as a transaction.

If forward_autocommit=true (false by default), the same behavior applies.

include/MySQL_Thread.h

@@ -364,6 +364,7 @@ class MySQL_Threads_Handler
 		bool forward_autocommit;
 		bool enforce_autocommit_on_reads;
 		bool autocommit_false_not_reusable;
+		bool autocommit_false_is_transaction;
 		int max_allowed_packet;
 		int throttle_connections_per_sec_to_hostgroup;
 		int max_transaction_time;

include/proxysql_structs.h

@@ -630,6 +630,7 @@ __thread bool mysql_thread___multiplexing;
 __thread bool mysql_thread___forward_autocommit;
 __thread bool mysql_thread___enforce_autocommit_on_reads;
 __thread bool mysql_thread___autocommit_false_not_reusable;
+__thread bool mysql_thread___autocommit_false_is_transaction;
 __thread bool mysql_thread___servers_stats;
 __thread bool mysql_thread___commands_stats;
 __thread bool mysql_thread___query_digests;
@@ -732,6 +733,7 @@ extern __thread bool mysql_thread___multiplexing;
 extern __thread bool mysql_thread___forward_autocommit;
 extern __thread bool mysql_thread___enforce_autocommit_on_reads;
 extern __thread bool mysql_thread___autocommit_false_not_reusable;
+extern __thread bool mysql_thread___autocommit_false_is_transaction;
 extern __thread bool mysql_thread___servers_stats;
 extern __thread bool mysql_thread___commands_stats;
 extern __thread bool mysql_thread___query_digests;

lib/MySQL_Session.cpp

@@ -1111,6 +1111,9 @@ bool MySQL_Session::handler_again___verify_init_connect() {
 }
 
 bool MySQL_Session::handler_again___verify_backend_autocommit() {
+	if (mysql_thread___forward_autocommit == true) {
+		return false;
+	}
 	if (autocommit != mybe->server_myds->myconn->IsAutoCommit()) {
 		// see case #485
 		if (mysql_thread___enforce_autocommit_on_reads == false) {

lib/MySQL_Thread.cpp

@@ -250,6 +250,7 @@ static char * mysql_thread_variables_names[]= {
 	(char *)"forward_autocommit",
 	(char *)"enforce_autocommit_on_reads",
 	(char *)"autocommit_false_not_reusable",
+	(char *)"autocommit_false_is_transaction",
 	(char *)"hostgroup_manager_verbose",
 	(char *)"threshold_query_length",
 	(char *)"threshold_resultset_size",
@@ -400,6 +401,7 @@ MySQL_Threads_Handler::MySQL_Threads_Handler() {
 	variables.forward_autocommit=false;
 	variables.enforce_autocommit_on_reads=false;
 	variables.autocommit_false_not_reusable=false;
+	variables.autocommit_false_is_transaction=false;
 	variables.query_digests=true;
 	variables.query_digests_lowercase=false;
 	variables.connpoll_reset_queue_length = 50;
@@ -648,6 +650,7 @@ int MySQL_Threads_Handler::get_variable_int(char *name) {
 	if (!strcasecmp(name,"forward_autocommit")) return (int)variables.forward_autocommit;
 	if (!strcasecmp(name,"enforce_autocommit_on_reads")) return (int)variables.enforce_autocommit_on_reads;
 	if (!strcasecmp(name,"autocommit_false_not_reusable")) return (int)variables.autocommit_false_not_reusable;
+	if (!strcasecmp(name,"autocommit_false_is_transaction")) return (int)variables.autocommit_false_is_transaction;
 	if (!strcasecmp(name,"commands_stats")) return (int)variables.commands_stats;
 	if (!strcasecmp(name,"query_digests")) return (int)variables.query_digests;
 	if (!strcasecmp(name,"query_digests_lowercase")) return (int)variables.query_digests_lowercase;
@@ -1004,6 +1007,9 @@ char * MySQL_Threads_Handler::get_variable(char *name) {	// this is the public f
 	if (!strcasecmp(name,"autocommit_false_not_reusable")) {
 		return strdup((variables.autocommit_false_not_reusable ? "true" : "false"));
 	}
+	if (!strcasecmp(name,"autocommit_false_is_transaction")) {
+		return strdup((variables.autocommit_false_is_transaction ? "true" : "false"));
+	}
 	if (!strcasecmp(name,"commands_stats")) {
 		return strdup((variables.commands_stats ? "true" : "false"));
 	}
@@ -1835,6 +1841,17 @@ bool MySQL_Threads_Handler::set_variable(char *name, char *value) {	// this is t
 		}
 		return false;
 	}
+	if (!strcasecmp(name,"autocommit_false_is_transaction")) {
+		if (strcasecmp(value,"true")==0 || strcasecmp(value,"1")==0) {
+			variables.autocommit_false_is_transaction=true;
+			return true;
+		}
+		if (strcasecmp(value,"false")==0 || strcasecmp(value,"0")==0) {
+			variables.autocommit_false_is_transaction=false;
+			return true;
+		}
+		return false;
+	}
 	if (!strcasecmp(name,"commands_stats")) {
 		if (strcasecmp(value,"true")==0 || strcasecmp(value,"1")==0) {
 			variables.commands_stats=true;
@@ -3245,6 +3262,7 @@ void MySQL_Thread::refresh_variables() {
 	mysql_thread___forward_autocommit=(bool)GloMTH->get_variable_int((char *)"forward_autocommit");
 	mysql_thread___enforce_autocommit_on_reads=(bool)GloMTH->get_variable_int((char *)"enforce_autocommit_on_reads");
 	mysql_thread___autocommit_false_not_reusable=(bool)GloMTH->get_variable_int((char *)"autocommit_false_not_reusable");
+	mysql_thread___autocommit_false_is_transaction=(bool)GloMTH->get_variable_int((char *)"autocommit_false_is_transaction");
 	mysql_thread___commands_stats=(bool)GloMTH->get_variable_int((char *)"commands_stats");
 	mysql_thread___query_digests=(bool)GloMTH->get_variable_int((char *)"query_digests");
 	mysql_thread___query_digests_lowercase=(bool)GloMTH->get_variable_int((char *)"query_digests_lowercase");

lib/mysql_connection.cpp

@@ -1471,6 +1471,12 @@ bool MySQL_Connection::IsActiveTransaction() {
 		if (ret == false && (mysql)->net.last_errno) {
 			ret = true;
 		}
+		if (ret == false) {
+			bool r = ( mysql_thread___autocommit_false_is_transaction || mysql_thread___forward_autocommit );
+			if ( r && (IsAutoCommit() == false) ) {
+				ret = true;
+			}
+		}
 	}
 	return ret;
 }