diff --git a/include/proxysql_config.h b/include/proxysql_config.h
index bc095b76c..1a98cce35 100644
--- a/include/proxysql_config.h
+++ b/include/proxysql_config.h
@@ -7,8 +7,8 @@ class SQLite3DB;
 extern const char* config_header;
 
 class ProxySQL_Config {
-	SQLite3DB* admindb;
 public:
+	SQLite3DB* admindb;
 	ProxySQL_Config(SQLite3DB* db);
 	virtual ~ProxySQL_Config();
 
diff --git a/include/proxysql_glovars.hpp b/include/proxysql_glovars.hpp
index 097708c0b..6b8b299f4 100644
--- a/include/proxysql_glovars.hpp
+++ b/include/proxysql_glovars.hpp
@@ -92,6 +92,7 @@ class ProxySQL_GlobalVariables {
 #ifdef PROXYSQLCLICKHOUSE
 		bool clickhouse_server;
 #endif /* PROXYSQLCLICKHOUSE */
+		pthread_mutex_t ext_glomth_mutex;
 	} global;
 	struct mysql {
 		char *server_version;
diff --git a/include/proxysql_restapi.h b/include/proxysql_restapi.h
index 9660a1264..b1de2bd82 100644
--- a/include/proxysql_restapi.h
+++ b/include/proxysql_restapi.h
@@ -22,8 +22,8 @@ public:
 };
 
 class ProxySQL_Restapi {
-	SQLite3DB* admindb;
 public:
+	SQLite3DB* admindb;
 	ProxySQL_Restapi(SQLite3DB* db);
 	virtual ~ProxySQL_Restapi();
 
diff --git a/lib/MySQL_Thread.cpp b/lib/MySQL_Thread.cpp
index 5675e1feb..d7abc6e7d 100644
--- a/lib/MySQL_Thread.cpp
+++ b/lib/MySQL_Thread.cpp
@@ -4733,6 +4733,7 @@ void MySQL_Thread::process_all_sessions() {
 }
 
 void MySQL_Thread::refresh_variables() {
+	pthread_mutex_lock(&GloVars.global.ext_glomth_mutex);
 	if (GloMTH==NULL) {
 		return;
 	}
@@ -4912,6 +4913,7 @@ void MySQL_Thread::refresh_variables() {
 	mysql_thread___session_debug=(bool)GloMTH->get_variable_int((char *)"session_debug");
 #endif /* DEBUG */
 	GloMTH->wrunlock();
+	pthread_mutex_unlock(&GloVars.global.ext_glomth_mutex);
 }
 
 MySQL_Thread::MySQL_Thread() {
diff --git a/lib/ProxySQL_Admin.cpp b/lib/ProxySQL_Admin.cpp
index 0dd2d40c0..b228af85c 100644
--- a/lib/ProxySQL_Admin.cpp
+++ b/lib/ProxySQL_Admin.cpp
@@ -778,11 +778,17 @@ int ProxySQL_Test___GetDigestTable(bool reset, bool use_swap) {
 
 ProxySQL_Config& ProxySQL_Admin::proxysql_config() {
 	static ProxySQL_Config instance = ProxySQL_Config(admindb);
+	if (instance.admindb != admindb) {
+		instance.admindb = admindb;
+	}
 	return instance;
 }
 
 ProxySQL_Restapi& ProxySQL_Admin::proxysql_restapi() {
 	static ProxySQL_Restapi instance = ProxySQL_Restapi(admindb);
+	if (instance.admindb != admindb) {
+		instance.admindb = admindb;
+	}
 	return instance;
 }
 
@@ -1200,7 +1206,13 @@ bool admin_handler_command_proxysql(char *query_no_space, unsigned int query_no_
 			rc=__sync_bool_compare_and_swap(&GloVars.global.nostart,1,0);
 		}
 		if (rc) {
+			// Set the status variable 'threads_initialized' to 0 because it's initialized back
+			// in main 'init_phase3'. After GloMTH have been initialized again.
+			__sync_bool_compare_and_swap(&GloMTH->status_variables.threads_initialized, 1, 0);
 			proxy_debug(PROXY_DEBUG_ADMIN, 4, "Starting ProxySQL following PROXYSQL START command\n");
+			while(__sync_fetch_and_add(&GloMTH->status_variables.threads_initialized, 0) == 1) {
+				usleep(1000);
+			}
 			SPA->send_MySQL_OK(&sess->client_myds->myprot, NULL);
 		} else {
 			proxy_warning("ProxySQL was already started when received PROXYSQL START command\n");
@@ -1231,6 +1243,17 @@ bool admin_handler_command_proxysql(char *query_no_space, unsigned int query_no_
 		GloMTH->commit();
 		glovars.reload=2;
 		__sync_bool_compare_and_swap(&glovars.shutdown,0,1);
+		// After setting the shutdown flag, we should wake all threads and wait for
+		// the shutdown phase to complete.
+		GloMTH->signal_all_threads(0);
+		while (__sync_fetch_and_add(&glovars.shutdown,0)==1) {
+			usleep(1000);
+		}
+		// After shutdown phase is completed, we must to send a 'OK' to the
+		// mysql client, otherwise, since this session might not be drop due
+		// to the waiting condition, the client wont disconnect and will
+		// keep forever waiting for acknowledgement.
+		SPA->send_MySQL_OK(&sess->client_myds->myprot, NULL);
 		return false;
 	}
 
@@ -4605,6 +4628,7 @@ void ProxySQL_Admin::vacuum_stats(bool is_admin) {
 
 
 void *child_mysql(void *arg) {
+	if (GloMTH == nullptr) { return NULL; }
 
 	pthread_attr_t thread_attr;
 	size_t tmp_stack_size=0;
diff --git a/lib/ProxySQL_GloVars.cpp b/lib/ProxySQL_GloVars.cpp
index 44570d7ad..323e7949b 100644
--- a/lib/ProxySQL_GloVars.cpp
+++ b/lib/ProxySQL_GloVars.cpp
@@ -100,6 +100,7 @@ ProxySQL_GlobalVariables::ProxySQL_GlobalVariables() :
 //	global.use_proxysql_mem=false;
 	pthread_mutex_init(&global.start_mutex,NULL);
 	pthread_mutex_init(&checksum_mutex,NULL);
+	pthread_mutex_init(&global.ext_glomth_mutex,NULL);
 	epoch_version = 0;
 	checksums_values.updates_cnt = 0;
 	checksums_values.dumped_at = 0;
diff --git a/src/main.cpp b/src/main.cpp
index 0e1427878..59c139831 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -766,6 +766,7 @@ void * mysql_worker_thread_func(void *arg) {
 	worker->run();
 	//delete worker;
 	delete worker;
+	mysql_thread->worker=NULL;
 //	l_mem_destroy(__thr_sfp);
 	__sync_fetch_and_sub(&GloVars.statuses.stack_memory_mysql_threads,tmp_stack_size);
 	return NULL;
@@ -1172,8 +1173,10 @@ void ProxySQL_Main_shutdown_all_modules() {
 	}
 	if (GloMTH) {
 		cpu_timer t;
+		pthread_mutex_lock(&GloVars.global.ext_glomth_mutex);
 		delete GloMTH;
 		GloMTH=NULL;
+		pthread_mutex_unlock(&GloVars.global.ext_glomth_mutex);
 #ifdef DEBUG
 		std::cerr << "GloMTH shutdown in ";
 #endif