diff --git a/include/MySQL_HostGroups_Manager.h b/include/MySQL_HostGroups_Manager.h
index e1df6480f..8f21cb56f 100644
--- a/include/MySQL_HostGroups_Manager.h
+++ b/include/MySQL_HostGroups_Manager.h
@@ -390,6 +390,89 @@ class MySQL_HostGroups_Manager {
 #else
 	rwlock_t rwlock;
 #endif
+
+	enum HGM_TABLES {
+		MYSQL_SERVERS = 0,
+		MYSQL_REPLICATION_HOSTGROUPS,
+		MYSQL_GROUP_REPLICATION_HOSTGROUPS,
+		MYSQL_GALERA_HOSTGROUPS,
+		MYSQL_AWS_AURORA_HOSTGROUPS,
+		MYSQL_HOSTGROUP_ATTRIBUTES,
+
+		__HGM_TABLES_SIZE
+	};
+
+	std::array<uint64_t, __HGM_TABLES_SIZE> table_resultset_checksum;
+
+	class HostGroup_Server_Mapping {
+	public:
+		enum Type {
+			WRITER = 0,
+			READER = 1
+		};
+
+		struct Node {
+			MySrvC* srv = NULL;
+			unsigned int reader_hostgroup_id = -1;
+			unsigned int writer_hostgroup_id = -1;
+			MySerStatus server_status = MYSQL_SERVER_STATUS_OFFLINE_HARD;
+		};
+
+		HostGroup_Server_Mapping() : readonly_flag(1), myHGM(NULL) { }
+		~HostGroup_Server_Mapping() = default;
+
+		// Note: copy, remove, clear method also makes changes to MyHostGroups
+		void copy(Type dest_type, Type src_type, bool update_if_exists = true);
+		void remove(Type type, size_t index);
+		void clear(Type type);
+		//
+
+		inline
+		const std::vector<Node>& get(Type type) const {
+			return mapping[type];
+		}
+
+		inline
+		void add(Type type, Node& node) {
+			mapping[type].push_back(node);
+		}
+
+		inline
+		void set(Type type, const std::vector<Node>& nodes) {
+			mapping[type] = nodes;
+		}
+
+		inline
+		void set_readonly_flag(int val) {
+			readonly_flag = val;
+		}
+
+		inline
+		int get_readonly_flag() const {
+			return readonly_flag;
+		}
+
+		inline
+		void set_HGM(MySQL_HostGroups_Manager* hgm) {
+			myHGM = hgm;
+		}
+
+	private:
+		unsigned int get_hostgroup_id(Type type, size_t index) const;
+		unsigned int get_hostgroup_id(Type type, const Node& node) const;
+		MySrvC* insert_HGM(unsigned int hostgroup_id, const MySrvC* srv);
+		void remove_HGM(MySrvC* srv);
+
+		std::array<std::vector<Node>, 2> mapping;
+		int readonly_flag;
+		MySQL_HostGroups_Manager* myHGM;
+	};
+
+	std::unordered_map<std::string, HostGroup_Server_Mapping> hostgroup_server_mapping;
+	uint64_t hgsm_mysql_servers_checksum = 0;
+	uint64_t hgsm_mysql_replication_hostgroups_checksum = 0;
+
+
 	PtrArray *MyHostGroups;
 	std::unordered_map<unsigned int, MyHGC *>MyHostGroups_map;
 
@@ -601,7 +684,7 @@ class MySQL_HostGroups_Manager {
 	int servers_add(SQLite3_result *resultset);
 	bool commit(SQLite3_result* runtime_mysql_servers = nullptr, const std::string& checksum = "", const time_t epoch = 0);
 	void commit_update_checksums_from_tables(SpookyHash& myhash, bool& init);
-	void CUCFT1(SpookyHash& myhash, bool& init, const string& TableName, const string& ColumnName); // used by commit_update_checksums_from_tables()
+	void CUCFT1(SpookyHash& myhash, bool& init, const string& TableName, const string& ColumnName, uint64_t& raw_checksum); // used by commit_update_checksums_from_tables()
 
 	/**
 	 * @brief Store the resultset for the 'runtime_mysql_servers' table set that have been loaded to runtime.
@@ -653,6 +736,7 @@ class MySQL_HostGroups_Manager {
 	void replication_lag_action_inner(MyHGC *, char*, unsigned int, int);
 	void replication_lag_action(int, char*, unsigned int, int);
 	void read_only_action(char *hostname, int port, int read_only);
+	void read_only_action_v2(const std::list<std::tuple<std::string,int,int>>& mysql_servers);
 	unsigned int get_servers_table_version();
 	void wait_servers_table_version(unsigned, unsigned);
 	bool shun_and_killall(char *hostname, int port);
diff --git a/lib/MySQL_HostGroups_Manager.cpp b/lib/MySQL_HostGroups_Manager.cpp
index a1ce67237..339a1dfa0 100644
--- a/lib/MySQL_HostGroups_Manager.cpp
+++ b/lib/MySQL_HostGroups_Manager.cpp
@@ -1586,7 +1586,7 @@ SQLite3_result * MySQL_HostGroups_Manager::execute_query(char *query, char **err
 	return resultset;
 }
 
-void MySQL_HostGroups_Manager::CUCFT1(SpookyHash& myhash, bool& init, const string& TableName, const string& ColumnName) {
+void MySQL_HostGroups_Manager::CUCFT1(SpookyHash& myhash, bool& init, const string& TableName, const string& ColumnName, uint64_t& raw_checksum) {
 	char *error=NULL;
 	int cols=0;
 	int affected_rows=0;
@@ -1600,6 +1600,7 @@ void MySQL_HostGroups_Manager::CUCFT1(SpookyHash& myhash, bool& init, const stri
 				myhash.Init(19,3);
 			}
 			uint64_t hash1_ = resultset->raw_checksum();
+			raw_checksum = hash1_;
 			myhash.Update(&hash1_, sizeof(hash1_));
 			proxy_info("Checksum for table %s is 0x%lX\n", TableName.c_str(), hash1_);
 		}
@@ -1610,11 +1611,11 @@ void MySQL_HostGroups_Manager::CUCFT1(SpookyHash& myhash, bool& init, const stri
 }
 
 void MySQL_HostGroups_Manager::commit_update_checksums_from_tables(SpookyHash& myhash, bool& init) {
-	CUCFT1(myhash,init,"mysql_replication_hostgroups","writer_hostgroup");
-	CUCFT1(myhash,init,"mysql_group_replication_hostgroups","writer_hostgroup");
-	CUCFT1(myhash,init,"mysql_galera_hostgroups","writer_hostgroup");
-	CUCFT1(myhash,init,"mysql_aws_aurora_hostgroups","writer_hostgroup");
-	CUCFT1(myhash,init,"mysql_hostgroup_attributes","hostgroup_id");
+	CUCFT1(myhash,init,"mysql_replication_hostgroups","writer_hostgroup", table_resultset_checksum[HGM_TABLES::MYSQL_REPLICATION_HOSTGROUPS]);
+	CUCFT1(myhash,init,"mysql_group_replication_hostgroups","writer_hostgroup", table_resultset_checksum[HGM_TABLES::MYSQL_GROUP_REPLICATION_HOSTGROUPS]);
+	CUCFT1(myhash,init,"mysql_galera_hostgroups","writer_hostgroup", table_resultset_checksum[HGM_TABLES::MYSQL_GALERA_HOSTGROUPS]);
+	CUCFT1(myhash,init,"mysql_aws_aurora_hostgroups","writer_hostgroup", table_resultset_checksum[HGM_TABLES::MYSQL_AWS_AURORA_HOSTGROUPS]);
+	CUCFT1(myhash,init,"mysql_hostgroup_attributes","hostgroup_id", table_resultset_checksum[HGM_TABLES::MYSQL_HOSTGROUP_ATTRIBUTES]);
 }
 
 bool MySQL_HostGroups_Manager::commit(
@@ -1867,8 +1868,9 @@ bool MySQL_HostGroups_Manager::commit(
 	}
 
 
-	if ( GloAdmin && GloAdmin->checksum_variables.checksum_mysql_servers ) {
-		uint64_t hash1=0, hash2=0;
+	//if (GloAdmin && GloAdmin->checksum_variables.checksum_mysql_servers) 
+	{
+		uint64_t hash1 = 0, hash2 = 0;
 		SpookyHash myhash;
 		char buf[80];
 		bool init = false;
@@ -1919,6 +1921,9 @@ bool MySQL_HostGroups_Manager::commit(
 						myhash.Init(19,3);
 					}
 					uint64_t hash1_ = resultset->raw_checksum();
+
+					table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS] = hash1_;
+
 					myhash.Update(&hash1_, sizeof(hash1_));
 					proxy_info("Checksum for table %s is 0x%lX\n", "mysql_servers", hash1_);
 				}
@@ -1953,6 +1958,58 @@ bool MySQL_HostGroups_Manager::commit(
 		pthread_mutex_unlock(&GloVars.checksum_mutex);
 	}
 
+	// fill Hostgroup_Manager_Mapping with latest records
+	if (hgsm_mysql_servers_checksum != table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS] ||
+		hgsm_mysql_replication_hostgroups_checksum != table_resultset_checksum[HGM_TABLES::MYSQL_REPLICATION_HOSTGROUPS])
+	{
+		proxy_info("Checksum for table 'mysql_servers': old:0x%lX new:0x%lX\n", hgsm_mysql_servers_checksum, table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS]);
+		proxy_info("Checksum for table 'mysql_replication_hostgroups': old:0x%lX new:0x%lX\n", hgsm_mysql_replication_hostgroups_checksum, table_resultset_checksum[HGM_TABLES::MYSQL_REPLICATION_HOSTGROUPS]);
+		
+		char* error = NULL;
+		int cols = 0;
+		int affected_rows = 0;
+		SQLite3_result* resultset = NULL;
+
+		const char* query = "SELECT DISTINCT hostname, port, '1' is_writer, status, reader_hostgroup, writer_hostgroup, mem_pointer FROM mysql_replication_hostgroups JOIN mysql_servers ON hostgroup_id=writer_hostgroup \
+							 UNION \
+							 SELECT DISTINCT hostname, port, '0' is_writer, status, reader_hostgroup, writer_hostgroup, mem_pointer FROM mysql_replication_hostgroups JOIN mysql_servers ON hostgroup_id=reader_hostgroup \
+							 ORDER BY hostname, port";
+		
+		mydb->execute_statement(query, &error, &cols, &affected_rows, &resultset);
+
+		hostgroup_server_mapping.clear();
+
+		if (resultset && resultset->rows_count) {
+			std::string fetched_server_id;
+			HostGroup_Server_Mapping* fetched_server_mapping = NULL;
+
+			for (std::vector<SQLite3_row*>::iterator it = resultset->rows.begin(); it != resultset->rows.end(); ++it) {
+				SQLite3_row* r = *it;
+
+				const std::string& server_id = std::string(r->fields[0]) + ":::" + r->fields[1];
+
+				if (fetched_server_mapping == NULL || server_id != fetched_server_id) {
+					fetched_server_mapping = &hostgroup_server_mapping[server_id];
+					fetched_server_mapping->set_HGM(this);
+					fetched_server_id = server_id;
+				}
+				
+				HostGroup_Server_Mapping::Node node;
+				node.server_status = static_cast<MySerStatus>(atoi(r->fields[3]));
+				node.reader_hostgroup_id = atoi(r->fields[4]);
+				node.writer_hostgroup_id = atoi(r->fields[5]);
+				node.srv = reinterpret_cast<MySrvC*>(atoll(r->fields[6]));
+				
+				HostGroup_Server_Mapping::Type type = (r->fields[2] && r->fields[2][0] == '1') ? HostGroup_Server_Mapping::Type::WRITER : HostGroup_Server_Mapping::Type::READER;
+				fetched_server_mapping->add(type, node);
+			}
+		}
+		delete resultset;
+
+		hgsm_mysql_servers_checksum = table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS];
+		hgsm_mysql_replication_hostgroups_checksum = table_resultset_checksum[HGM_TABLES::MYSQL_REPLICATION_HOSTGROUPS];
+	}
+
 	ev_async_send(gtid_ev_loop, gtid_ev_async);
 
 	__sync_fetch_and_add(&status.servers_table_version,1);
@@ -4499,6 +4556,213 @@ void MySQL_HostGroups_Manager::read_only_action(char *hostname, int port, int re
 	free(query);
 }
 
+void MySQL_HostGroups_Manager::read_only_action_v2(const std::list<std::tuple<std::string,int,int>>& mysql_servers) {
+
+	std::string hostname;
+	int port = -1;
+	int read_only = -1;
+	bool update_mysql_servers_table = false;
+
+	unsigned long long curtime1 = monotonic_time();
+	wrlock();
+	for (const auto& server : mysql_servers) {
+		bool is_writer = false;
+		std::tie(hostname, port, read_only) = server;
+		const std::string& srv_id = hostname + ":::" + std::to_string(port);
+		
+		auto itr = hostgroup_server_mapping.find(srv_id);
+
+		if (itr == hostgroup_server_mapping.end()) {
+			assert(0);
+		}
+
+		HostGroup_Server_Mapping& host_server_mapping = itr->second;
+
+		const std::vector<HostGroup_Server_Mapping::Node>& writer_map = host_server_mapping.get(HostGroup_Server_Mapping::Type::WRITER);
+		const std::vector<HostGroup_Server_Mapping::Node>& reader_map = host_server_mapping.get(HostGroup_Server_Mapping::Type::READER);
+
+		bool removed_offline_server = false;
+
+		for (size_t i = 0; i < writer_map.size();) {
+
+			const HostGroup_Server_Mapping::Node& node = writer_map[i];
+
+			// remove offline hard server node from writer map
+			if (node.server_status == MYSQL_SERVER_STATUS_OFFLINE_HARD) {
+				proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 5, "Removing server %s:%d in hostgroup=%d having status='OFFLINE_HARD'\n", hostname.c_str(), port, node.writer_hostgroup_id);
+				host_server_mapping.remove(HostGroup_Server_Mapping::Type::WRITER, i);
+				removed_offline_server = true;
+				continue;
+			}
+
+			i++;
+		}
+
+		is_writer = !writer_map.empty();
+
+		if (read_only == 0) {
+			if (is_writer == false) {
+				// the server has read_only=0 (writer), but we can't find any writer, 
+				// so we copy all reader nodes to writer
+				host_server_mapping.copy(HostGroup_Server_Mapping::Type::WRITER, HostGroup_Server_Mapping::Type::READER);
+
+				if (mysql_thread___monitor_writer_is_also_reader) {
+					// server is also a reader, we copy all nodes from writer to reader (previous reader nodes will be reused)
+					host_server_mapping.copy(HostGroup_Server_Mapping::Type::READER, HostGroup_Server_Mapping::Type::WRITER, false);
+				} else {
+					// server can only be a writer
+					host_server_mapping.clear(HostGroup_Server_Mapping::Type::READER);
+				}
+
+				update_mysql_servers_table = true;
+			} else {
+				bool act = false;
+
+				// if the server was RO=0 on the previous check then no action is needed
+				if (host_server_mapping.get_readonly_flag() != 0) {
+					// it is the first time that we detect RO on this server
+					
+					act = removed_offline_server;
+
+					if (act == false) {
+						for (const auto& reader_node : reader_map) {
+							for (const auto& writer_node : writer_map) {
+
+								if (reader_node.writer_hostgroup_id == writer_node.writer_hostgroup_id) {
+									goto __writer_found;
+								}
+							}
+							act = true;
+							break;
+						__writer_found:
+							continue;
+						}
+					}
+
+					if (act == false) {
+						// no action required, therefore we set readonly_flag to 0
+						proxy_info("read_only_action_v2() detected RO=0 on server %s:%d for the first time after commit(), but no need to reconfigure\n", hostname.c_str(), port);
+						host_server_mapping.set_readonly_flag(0);
+					}
+				} else {
+					// the server was already detected as RO=0
+					// no action required
+				}
+
+				if (act == true) {	// there are servers either missing, or with stats=OFFLINE_HARD
+
+					// copy all reader nodes to writer
+					host_server_mapping.copy(HostGroup_Server_Mapping::Type::WRITER, HostGroup_Server_Mapping::Type::READER);
+
+					if (mysql_thread___monitor_writer_is_also_reader) {
+						// server is also a reader, we copy all nodes from writer to reader (previous reader nodes will be reused)
+						host_server_mapping.copy(HostGroup_Server_Mapping::Type::READER, HostGroup_Server_Mapping::Type::WRITER, false);
+					} else {
+						// server can only be a writer
+						host_server_mapping.clear(HostGroup_Server_Mapping::Type::READER);
+					}
+
+					update_mysql_servers_table = true;
+				}
+			}
+		} else if (read_only == 1) {
+			if (is_writer) {
+				// the server has read_only=1 (reader), but we find it as writer, so we copy all writer nodes to reader (previous reader nodes will be reused)
+				host_server_mapping.copy(HostGroup_Server_Mapping::Type::READER, HostGroup_Server_Mapping::Type::WRITER, false);
+
+				// clearing all writer nodes
+				host_server_mapping.clear(HostGroup_Server_Mapping::Type::WRITER);
+
+				update_mysql_servers_table = true;
+			}
+		} else {
+			// LCOV_EXCL_START
+			assert(0);
+			break;
+			// LCOV_EXCL_STOP
+		}
+	}
+
+	if (update_mysql_servers_table) {
+		purge_mysql_servers_table();
+		proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 4, "DELETE FROM mysql_servers\n");
+		mydb->execute("DELETE FROM mysql_servers");
+		generate_mysql_servers_table();
+
+		//if (GloAdmin && GloAdmin->checksum_variables.checksum_mysql_servers) 
+		{
+			char* error = NULL;
+			int cols = 0;
+			int affected_rows = 0;
+			SQLite3_result* resultset = NULL;
+			mydb->execute_statement(MYHGM_GEN_ADMIN_RUNTIME_SERVERS, &error, &cols, &affected_rows, &resultset);
+			save_runtime_mysql_servers(resultset); // assigning runtime_mysql_servers with updated mysql server resultset 
+			
+			resultset = NULL;
+
+			char* query = (char*)"SELECT hostgroup_id, hostname, port, gtid_port, CASE status WHEN 0 OR 1 OR 4 THEN 0 ELSE status END status, weight, compression, max_connections, max_replication_lag, use_ssl, max_latency_ms, comment FROM mysql_servers WHERE status<>3 ORDER BY hostgroup_id, hostname, port";
+			mydb->execute_statement(query, &error, &cols, &affected_rows, &resultset);
+
+			if (resultset) {
+				if (resultset->rows_count) {
+					table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS] = resultset->raw_checksum();
+
+					hgsm_mysql_servers_checksum = table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS];
+				}
+				delete resultset;
+			} else {
+				proxy_info("Checksum for table %s is 0x%lX\n", "mysql_servers", (long unsigned int)0);
+			}
+
+			uint64_t hash = 0, hash2 = 0;
+			SpookyHash myhash;
+
+			myhash.Init(19, 3);
+			hash = table_resultset_checksum[HGM_TABLES::MYSQL_SERVERS];
+			myhash.Update(&hash, sizeof(hash));
+
+			hash = table_resultset_checksum[HGM_TABLES::MYSQL_REPLICATION_HOSTGROUPS];
+			myhash.Update(&hash, sizeof(hash));
+
+			hash = table_resultset_checksum[HGM_TABLES::MYSQL_GROUP_REPLICATION_HOSTGROUPS];
+			myhash.Update(&hash, sizeof(hash));
+
+			hash = table_resultset_checksum[HGM_TABLES::MYSQL_GALERA_HOSTGROUPS];
+			myhash.Update(&hash, sizeof(hash));
+
+			hash = table_resultset_checksum[HGM_TABLES::MYSQL_AWS_AURORA_HOSTGROUPS];
+			myhash.Update(&hash, sizeof(hash));
+
+			hash = table_resultset_checksum[HGM_TABLES::MYSQL_HOSTGROUP_ATTRIBUTES];
+			myhash.Update(&hash, sizeof(hash));
+
+			myhash.Final(&hash, &hash2);
+
+			char buf[80];
+			uint32_t d32[2];
+			memcpy(&d32, &hash, sizeof(hash));
+			sprintf(buf, "0x%0X%0X", d32[0], d32[1]);
+			pthread_mutex_lock(&GloVars.checksum_mutex);
+			GloVars.checksums_values.mysql_servers.set_checksum(buf);
+			GloVars.checksums_values.mysql_servers.version++;
+			//struct timespec ts;
+			//clock_gettime(CLOCK_REALTIME, &ts);
+			time_t t = time(NULL);
+
+			GloVars.checksums_values.mysql_servers.epoch = t;
+
+			GloVars.checksums_values.updates_cnt++;
+			GloVars.generate_global_checksum();
+			GloVars.epoch_version = t;
+			pthread_mutex_unlock(&GloVars.checksum_mutex);
+		}
+	}
+	wrunlock();
+	unsigned long long curtime2 = monotonic_time();
+	curtime1 = curtime1 / 1000;
+	curtime2 = curtime2 / 1000;
+	proxy_info("MySQL_HostGroups_Manager::read_only_action_v2() locked for %llums\n", curtime2 - curtime1);
+}
 
 // shun_and_killall
 // this function is called only from MySQL_Monitor::monitor_ping()
@@ -7358,3 +7622,127 @@ MySrvC* MySQL_HostGroups_Manager::find_server_in_hg(unsigned int _hid, const std
 	return f_server;
 }
 
+void MySQL_HostGroups_Manager::HostGroup_Server_Mapping::copy(Type dest_type, Type src_type, bool update_if_exists /*= true*/) {
+
+	const std::vector<Node>& src_nodes = mapping[src_type];
+
+	if (src_nodes.empty()) return;
+
+	std::vector<Node>& dest_nodes = mapping[dest_type];
+	std::list<Node> append;
+
+	for (const auto& node : src_nodes) {
+
+		for (auto& parent_node : dest_nodes) {
+
+			if (node.reader_hostgroup_id == parent_node.reader_hostgroup_id &&
+				node.writer_hostgroup_id == parent_node.writer_hostgroup_id) {
+
+				if (update_if_exists) {
+					MySrvC* new_srv = insert_HGM(get_hostgroup_id(dest_type, parent_node), node.srv);
+
+					if (!new_srv) assert(0);
+					
+					parent_node.srv = new_srv;
+					parent_node.server_status = node.server_status;
+				}
+				goto __skip;
+			}
+		}
+
+		append.push_back(node);
+
+	__skip:
+		continue;
+	}
+
+	if (append.empty()) {
+		return;
+	}
+
+	if (dest_nodes.capacity() < (dest_nodes.size() + append.size()))
+		dest_nodes.reserve(dest_nodes.size() + append.size());
+	//dest_nodes.insert(dest_nodes.end(), append.begin(), append.end());
+
+	for (auto& node : append) {
+		MySrvC* new_srv = insert_HGM(get_hostgroup_id(dest_type, node), node.srv);
+			
+		if (!new_srv) assert(0);
+			
+		node.srv = new_srv;
+		dest_nodes.push_back(node);
+	}
+}
+
+void MySQL_HostGroups_Manager::HostGroup_Server_Mapping::remove(Type type, size_t index) {
+
+	std::vector<Node>& nodes = mapping[type];
+
+	// ensure that we're not attempting to access out of the bounds of the container.
+	assert(index < nodes.size());
+
+	remove_HGM(nodes[index].srv);
+
+	//Swap the element with the back element, except in the case when we're the last element.
+	if (index + 1 != nodes.size())
+		std::swap(nodes[index], nodes.back());
+
+	//Pop the back of the container, deleting our old element.
+	nodes.pop_back();
+}
+
+void MySQL_HostGroups_Manager::HostGroup_Server_Mapping::clear(Type type) {
+
+	for (const auto& node : mapping[type]) {
+		remove_HGM(node.srv);
+	}
+
+	mapping[type].clear();
+}
+
+unsigned int MySQL_HostGroups_Manager::HostGroup_Server_Mapping::get_hostgroup_id(Type type, size_t index) const {
+
+	if (type == Type::WRITER)
+		return mapping[Type::WRITER][index].writer_hostgroup_id;
+	else if (type == Type::READER)
+		return mapping[Type::READER][index].reader_hostgroup_id;
+	else
+		assert(0);
+}
+
+unsigned int MySQL_HostGroups_Manager::HostGroup_Server_Mapping::get_hostgroup_id(Type type, const Node& node) const {
+
+	if (type == Type::WRITER)
+		return node.writer_hostgroup_id;
+	else if (type == Type::READER)
+		return node.reader_hostgroup_id;
+	else
+		assert(0);
+}
+
+MySrvC* MySQL_HostGroups_Manager::HostGroup_Server_Mapping::insert_HGM(unsigned int hostgroup_id, const MySrvC* srv) {
+
+	MyHGC* hostgroup_container = myHGM->MyHGC_lookup(hostgroup_id);
+
+	if (!hostgroup_container)
+		return NULL;
+
+	if (GloMTH->variables.hostgroup_manager_verbose) {
+		proxy_info("Creating new server in HG %d : %s:%d , gtid_port=%d, weight=%d, status=%d\n", hostgroup_id, srv->address, srv->port, srv->gtid_port, srv->weight, srv->status);
+	}
+
+	proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 5, "Adding new server %s:%d , weight=%d, status=%d, mem_ptr=%p into hostgroup=%d\n", srv->address, srv->port, srv->weight, srv->status, srv, hostgroup_id);
+
+	MySrvC* new_srv = new MySrvC(srv->address, srv->port, srv->gtid_port, srv->weight, srv->status, srv->compression,
+		srv->max_connections, srv->max_replication_lag, srv->use_ssl, srv->max_latency_us, srv->comment);
+
+	hostgroup_container->mysrvs->add(new_srv);
+
+	return new_srv;
+}
+
+void MySQL_HostGroups_Manager::HostGroup_Server_Mapping::remove_HGM(MySrvC* srv) {
+	proxy_warning("Removed server at address %p, hostgroup %d, address %s port %d. Setting status OFFLINE HARD and immediately dropping all free connections. Used connections will be dropped when trying to use them\n", (void*)srv, srv->myhgc->hid, srv->address, srv->port);
+	srv->status = MYSQL_SERVER_STATUS_OFFLINE_HARD;
+	srv->ConnectionsFree->drop_all_connections();
+}
\ No newline at end of file
diff --git a/lib/MySQL_Monitor.cpp b/lib/MySQL_Monitor.cpp
index f258a6fe7..dbbda2009 100644
--- a/lib/MySQL_Monitor.cpp
+++ b/lib/MySQL_Monitor.cpp
@@ -1716,7 +1716,7 @@ VALGRIND_ENABLE_ERROR_REPORTING;
 		}
 
 		if (timeout_reached == false && mmsd->interr == 0) {
-			MyHGM->read_only_action(mmsd->hostname, mmsd->port, read_only); // default behavior
+			MyHGM->read_only_action_v2({ { mmsd->hostname, mmsd->port, read_only } }); // default behavior
 		} else {
 			char *error=NULL;
 			int cols=0;
@@ -1735,7 +1735,7 @@ VALGRIND_ENABLE_ERROR_REPORTING;
 						// disable host
 						proxy_error("Server %s:%d missed %d read_only checks. Assuming read_only=1\n", mmsd->hostname, mmsd->port, max_failures);
 						MyHGM->p_update_mysql_error_counter(p_mysql_error_type::proxysql, mmsd->hostgroup_id, mmsd->hostname, mmsd->port, ER_PROXYSQL_READ_ONLY_CHECKS_MISSED);
-						MyHGM->read_only_action(mmsd->hostname, mmsd->port, read_only); // N timeouts reached
+						MyHGM->read_only_action_v2({ { mmsd->hostname, mmsd->port, read_only } }); // N timeouts reached
 					}
 					delete resultset;
 					resultset=NULL;
@@ -7089,6 +7089,8 @@ __again:
 
 bool MySQL_Monitor::monitor_read_only_process_ready_tasks(const std::vector<MySQL_Monitor_State_Data*>& mmsds) {
 
+	std::list<std::tuple<std::string, int, int>> mysql_servers;
+
 	for (auto& mmsd : mmsds) {
 
 		const auto task_result = mmsd->get_task_result();
@@ -7181,7 +7183,8 @@ VALGRIND_ENABLE_ERROR_REPORTING;
 		(*proxy_sqlite3_finalize)(statement);
 
 		if (task_result == MySQL_Monitor_State_Data_Task_Result::TASK_RESULT_SUCCESS) {
-			MyHGM->read_only_action(mmsd->hostname, mmsd->port, read_only); // default behavior
+			//MyHGM->read_only_action_v2(mmsd->hostname, mmsd->port, read_only); // default behavior
+			mysql_servers.push_back({ mmsd->hostname, mmsd->port, read_only });
 		} else {
 			char* error = NULL;
 			int cols = 0;
@@ -7200,7 +7203,8 @@ VALGRIND_ENABLE_ERROR_REPORTING;
 						// disable host
 						proxy_error("Server %s:%d missed %d read_only checks. Assuming read_only=1\n", mmsd->hostname, mmsd->port, max_failures);
 						MyHGM->p_update_mysql_error_counter(p_mysql_error_type::proxysql, mmsd->hostgroup_id, mmsd->hostname, mmsd->port, ER_PROXYSQL_READ_ONLY_CHECKS_MISSED);
-						MyHGM->read_only_action(mmsd->hostname, mmsd->port, read_only); // N timeouts reached
+						//MyHGM->read_only_action_v2(mmsd->hostname, mmsd->port, read_only); // N timeouts reached
+						mysql_servers.push_back({ mmsd->hostname, mmsd->port, read_only });
 					}
 					delete resultset;
 					resultset = NULL;
@@ -7212,6 +7216,9 @@ VALGRIND_ENABLE_ERROR_REPORTING;
 		}
 	}
 
+	//executing readonly actions
+	MyHGM->read_only_action_v2(mysql_servers);
+
 	return true;
 }
 
diff --git a/lib/ProxySQL_Admin.cpp b/lib/ProxySQL_Admin.cpp
index ca8283b9c..abc9cd623 100644
--- a/lib/ProxySQL_Admin.cpp
+++ b/lib/ProxySQL_Admin.cpp
@@ -13447,9 +13447,9 @@ unsigned long long ProxySQL_Admin::ProxySQL_Test___MySQL_HostGroups_Manager_read
 			sprintf(hostnamebuf1,"hostname%d", i*10+1);
 			sprintf(hostnamebuf2,"hostname%d", i*10+2);
 			sprintf(hostnamebuf3,"hostname%d", i*10+3);
-			MyHGM->read_only_action(hostnamebuf1, 3306, 0);
-			MyHGM->read_only_action(hostnamebuf2, 3306, 1);
-			MyHGM->read_only_action(hostnamebuf3, 3306, 1);
+			MyHGM->read_only_action_v2({ { std::string(hostnamebuf1), 3306, 0 },
+										 { std::string(hostnamebuf2), 3306, 1 },
+										 { std::string(hostnamebuf3), 3306, 1 } });
 		}
 	}
 	unsigned long long t2 = monotonic_time();