Heap allocated host pointer for async mysql_real_connect_start function

Few fixes

include/MySQL_HostGroups_Manager.h

@@ -131,6 +131,7 @@ class MySrvC {	// MySQL Server Container
 	public:
 	MyHGC *myhgc;
 	char *address;
+	char* resolved_ip;
 	uint16_t port;
 	uint16_t gtid_port;
 	uint16_t flags;

include/MySQL_Monitor.hpp

@@ -309,7 +309,7 @@ public:
 	bool add(const std::string& hostname, const std::string& ip);
 	void remove(const std::string& hostname);
 	void clear();
-	std::string lookup(const std::string& hostname, bool return_hostname_if_lookup_fails) const;
+	std::string lookup(const std::string& hostname) const;
 	void bulk_update(const std::list<std::pair<DNS_Cache_Record, OPERATION>> bulk_record);
 
 private:
@@ -329,8 +329,8 @@ struct DNS_Resolve_Data {
 
 class MySQL_Monitor {
 	public:
-	static std::string dns_lookup(const std::string& hostname);
-	static std::string dns_lookup(const char* hostname);
+	static std::string dns_lookup(const std::string& hostname, bool return_hostname_if_lookup_fails = true);
+	static std::string dns_lookup(const char* hostname, bool return_hostname_if_lookup_fails = true);
 
 	private:
 	std::vector<table_def_t *> *tables_defs_monitor;

lib/MySQL_HostGroups_Manager.cpp

@@ -839,7 +839,7 @@ void MySrvConnList::drop_all_connections() {
 }
 
 
-MySrvC::MySrvC(char *add, uint16_t p, uint16_t gp, unsigned int _weight, enum MySerStatus _status, unsigned int _compression /*, uint8_t _charset */, unsigned int _max_connections, unsigned int _max_replication_lag, unsigned int _use_ssl, unsigned int _max_latency_ms, char *_comment) {
+MySrvC::MySrvC(char *add, uint16_t p, uint16_t gp, unsigned int _weight, enum MySerStatus _status, unsigned int _compression /*, uint8_t _charset */, unsigned int _max_connections, unsigned int _max_replication_lag, unsigned int _use_ssl, unsigned int _max_latency_ms, char *_comment) : resolved_ip(NULL) {
 	address=strdup(add);
 	port=p;
 	gtid_port=gp;
@@ -951,6 +951,7 @@ void MySrvC::shun_and_killall() {
 MySrvC::~MySrvC() {
 	if (address) free(address);
 	if (comment) free(comment);
+	if (resolved_ip) free(resolved_ip);
 	delete ConnectionsUsed;
 	delete ConnectionsFree;
 }

lib/MySQL_Monitor.cpp

@@ -5425,28 +5425,31 @@ void MySQL_Monitor::evaluate_aws_aurora_results(unsigned int wHG, unsigned int r
 #endif // TEST_AURORA
 }
 
-std::string MySQL_Monitor::dns_lookup(const std::string& hostname) {
+std::string MySQL_Monitor::dns_lookup(const std::string& hostname, bool return_hostname_if_lookup_fails) {
 	
 	// if IP was provided, no need to do lookup
 	if (validate_ip(hostname))
 		return hostname;
 
 	static thread_local std::shared_ptr<DNS_Cache> dns_cache_thread;
-	const std::string& hostname_trim = trim(hostname);
 	std::string ip;
 
 	if (!dns_cache_thread && GloMyMon)
 		dns_cache_thread = GloMyMon->dns_cache;
 
 	if (dns_cache_thread) {
-		ip = dns_cache_thread->lookup(hostname_trim, false) ;
+		ip = dns_cache_thread->lookup(trim(hostname)) ;
+
+		if (ip.empty() && return_hostname_if_lookup_fails) {
+			ip = hostname;
+		}
 	}
 
-	return !ip.empty() ? ip : hostname_trim;
+	return ip;
 }
 
-std::string MySQL_Monitor::dns_lookup(const char* hostname) {
-	return MySQL_Monitor::dns_lookup(std::string(hostname));
+std::string MySQL_Monitor::dns_lookup(const char* hostname, bool return_hostname_if_lookup_fails) {
+	return MySQL_Monitor::dns_lookup(std::string(hostname), return_hostname_if_lookup_fails);
 }
 
 bool DNS_Cache::add(const std::string& hostname, const std::string& ip) {
@@ -5456,7 +5459,7 @@ bool DNS_Cache::add(const std::string& hostname, const std::string& ip) {
 	int rc = pthread_rwlock_wrlock(&rwlock_);
 	assert(rc == 0);
 	try {
-		records.emplace(hostname, ip);
+		records[hostname] = ip;
 	}
 	catch (...) {}
 	rc = pthread_rwlock_unlock(&rwlock_);
@@ -5468,7 +5471,7 @@ bool DNS_Cache::add(const std::string& hostname, const std::string& ip) {
 	return true;
 }
 
-std::string DNS_Cache::lookup(const std::string& hostname, bool return_hostname_if_lookup_fails) const {
+std::string DNS_Cache::lookup(const std::string& hostname) const {
 	if (!enabled) return "";
 
 	std::string ip;
@@ -5489,10 +5492,6 @@ std::string DNS_Cache::lookup(const std::string& hostname, bool return_hostname_
 		__sync_fetch_and_add(&GloMyMon->dns_cache_lookup_success, 1);
 	}
 
-	if (ip.empty() && return_hostname_if_lookup_fails) {
-		ip = hostname;
-	}
-
 	return ip;
 }
 

lib/mysql_connection.cpp

@@ -808,7 +808,29 @@ void MySQL_Connection::connect_start() {
 		}
 	}
 	if (parent->port) {
-		async_exit_status=mysql_real_connect_start(&ret_mysql, mysql, MySQL_Monitor::dns_lookup(parent->address).c_str(), userinfo->username, auth_password, userinfo->schemaname, parent->port, NULL, client_flags);
+
+		char* host_ip = NULL;
+		const std::string& res_ip = MySQL_Monitor::dns_lookup(parent->address, false);
+
+		if (!res_ip.empty()) {
+
+			if (parent->resolved_ip) {
+				if (strcmp(parent->resolved_ip, res_ip.c_str()) != 0) {
+					free(parent->resolved_ip);
+					parent->resolved_ip = strdup(res_ip.c_str());
+				}
+			}
+			else {
+				parent->resolved_ip = strdup(res_ip.c_str());
+			}
+
+			host_ip = parent->resolved_ip;
+		}
+		else {
+			host_ip = parent->address;
+		}
+
+		async_exit_status=mysql_real_connect_start(&ret_mysql, mysql, host_ip, userinfo->username, auth_password, userinfo->schemaname, parent->port, NULL, client_flags);
 	} else {
 		async_exit_status=mysql_real_connect_start(&ret_mysql, mysql, "localhost", userinfo->username, auth_password, userinfo->schemaname, parent->port, parent->address, client_flags);
 	}