diff --git a/include/MySQL_Session.h b/include/MySQL_Session.h
index 4efc00cf9..33fe271d8 100644
--- a/include/MySQL_Session.h
+++ b/include/MySQL_Session.h
@@ -584,6 +584,9 @@ class MySQL_Session: public Base_Session<MySQL_Session, MySQL_Data_Stream, MySQL
 
 	friend void SQLite3_Server_session_handler(MySQL_Session*, void *_pa, PtrSize_t *pkt);
 
+	MySQL_Session(const MySQL_Session&) = delete;
+	MySQL_Session& operator=(const MySQL_Session&) = delete;
+
 #if defined(__clang__)
 	template<typename SESS, typename DS, typename BE, typename THD>
 	friend class Base_Session;
@@ -611,6 +614,8 @@ public:
 	KillArgs(char *u, char *p, char *h, unsigned int P, unsigned int _hid, unsigned long i, int kt, int _use_ssl, MySQL_Thread* _mt, char *ip);
 	~KillArgs();
 	const char* get_host_address() const;
+	KillArgs(const KillArgs&) = delete;
+	KillArgs& operator=(const KillArgs&) = delete;
 
 private:
 	char* ip_addr;
diff --git a/lib/MySQL_HostGroups_Manager.cpp b/lib/MySQL_HostGroups_Manager.cpp
index 376d1ef56..83c584409 100644
--- a/lib/MySQL_HostGroups_Manager.cpp
+++ b/lib/MySQL_HostGroups_Manager.cpp
@@ -1877,7 +1877,7 @@ void MySQL_HostGroups_Manager::generate_mysql_servers_table(int *_onlyhg) {
 						st=(char *)"SHUNNED";
 						break;
 				}
-				fprintf(stderr,"HID: %d , address: %s , port: %d , gtid_port: %d , weight: %ld , status: %s , max_connections: %ld , max_replication_lag: %u , use_ssl: %u , max_latency_ms: %u , comment: %s\n", mysrvc->myhgc->hid, mysrvc->address, mysrvc->port, mysrvc->gtid_port, mysrvc->weight, st, mysrvc->max_connections, mysrvc->max_replication_lag, mysrvc->use_ssl, mysrvc->max_latency_us*1000, mysrvc->comment);
+				fprintf(stderr,"HID: %u , address: %s , port: %d , gtid_port: %d , weight: %ld , status: %s , max_connections: %ld , max_replication_lag: %u , use_ssl: %d , max_latency_ms: %u , comment: %s\n", mysrvc->myhgc->hid, mysrvc->address, mysrvc->port, mysrvc->gtid_port, mysrvc->weight, st, mysrvc->max_connections, mysrvc->max_replication_lag, mysrvc->use_ssl, mysrvc->max_latency_us*1000, mysrvc->comment);
 			}
 			lst->add(mysrvc);
 			if (lst->len==32) {
@@ -3578,8 +3578,9 @@ void MySQL_HostGroups_Manager::read_only_action_v2(const std::list<read_only_ser
 
 		HostGroup_Server_Mapping* host_server_mapping = itr->second.get();
 
-		if (!host_server_mapping)
-			assert(0);
+		if (!host_server_mapping) {
+			continue;
+		}
 
 		const std::vector<HostGroup_Server_Mapping::Node>& writer_map = host_server_mapping->get(HostGroup_Server_Mapping::Type::WRITER);
 
diff --git a/lib/MySQL_Session.cpp b/lib/MySQL_Session.cpp
index a2ecb18c8..38883df1e 100644
--- a/lib/MySQL_Session.cpp
+++ b/lib/MySQL_Session.cpp
@@ -9572,7 +9572,7 @@ char* MySQL_Session::get_current_query(int max_length) {
 
 	if (query_len > 0) {
 		res = (char *) malloc(query_len + 1);
-		if (trunc_query) {
+		if (trunc_query && query_len > 3) {
 			// for truncated queries, add three dots at the end
 			memcpy(res, query_ptr, query_len - 3);
 			memcpy(res + (query_len - 3), "...", 3);