BUG#26236857 - LRU_GET: ASSERTION `!IS_BUSY_MACHINE(&RETVAL->PAX)' FAILED (Post-Fix)

This patch maintains the removal of the assertion code, but reverts the part of the
patch that changes they way log_start is sent to other members and how new
incarnations nodes are seen by the system within XCom.

(cherry picked from commit 00d87720eecd2a411b7930574fc3b5c05296e651)

Author: tiagoportelajorge

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_base.c

@@ -425,10 +425,6 @@ static uint32_t	my_id = 0; /* Unique id of this instance */
 static synode_no current_message; /* Current message number */
 static synode_no last_config_modification_id; /*Last configuration change proposal*/
 
-uint32_t get_my_id(){
-	return my_id;
-}
-
 synode_no get_current_message()
 {
 	return current_message;
@@ -3964,9 +3960,6 @@ int	acceptor_learner_task(task_arg arg)
 			ceptor_learner_task.
 		*/
 		ep->srv = get_server(site, ep->p->from);
-		if(ep->rfd.x_proto > x_1_2){ /* Ignore nodes which do not send ID */
-			update_xcom_id(ep->p->from, (uint32_t)ep->p->refcnt); /* Refcnt is really uuid */
-		}
 		ep->p->refcnt = 1; /* Refcnt from other end is void here */
 		MAY_DBG(FN;
 				NDBG(ep->rfd.fd, d); NDBG(task_now(), f);
@@ -4123,9 +4116,6 @@ int	reply_handler_task(task_arg arg)
 				add_event(string_arg("ep->s->con.fd"));
 				add_event(int_arg(ep->s->con.fd));
 			);
-			if(ep->s->con.x_proto > x_1_2){ /* Ignore nodes which do not send ID */
-				update_xcom_id(ep->reply->from, (uint32_t)ep->reply->refcnt); /* Refcnt is really uuid */
-			}
 			ep->reply->refcnt = 1; /* Refcnt from other end is void here */
 			if (n <= 0) {
 				shutdown_connection(&ep->s->con);
@@ -4389,6 +4379,9 @@ static void	server_handle_need_snapshot(server *srv, site_def const *s, node_no
 	if (!synode_eq(null_synode, app_lsn) && synode_lt(app_lsn, gs->log_start)){
 		gs->log_start = app_lsn;
 	}
+	else if (!synode_eq(null_synode, last_config_modification_id)) {
+		gs->log_start = last_config_modification_id;
+	}
 
 	server_send_snapshot(srv, s, gs, node);
 	server_push_log(srv, gs->log_start, node);

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_base.h

@@ -219,7 +219,6 @@ int64_t xcom_client_send_data(uint32_t size, char *data,
                               connection_descriptor* fd);
 int	xcom_client_terminate_and_exit(connection_descriptor* fd);
 int	xcom_client_set_cache_limit(connection_descriptor *fd, uint64_t cache_limit);
-uint32_t get_my_id();
 
 static inline char *strerr_msg(char *buf, size_t len, int nr)
 {

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_detector.c

@@ -40,26 +40,6 @@ extern int	xcom_shutdown;
 
 /* static double	detected[NSERVERS]; */
 
-static struct{
-  int changed;
-  uint32_t id[NSERVERS];
-}id_tracker;
-
-void update_xcom_id(node_no node, uint32_t id){
-  if(node < NSERVERS && id_tracker.id[node] != id){
-    id_tracker.changed = 1;
-    id_tracker.id[node] = id;
-  }
-}
-
-static int xcom_id_changed(){
-  return id_tracker.changed;
-}
-
-static void reset_id_changed(){
-  id_tracker.changed = 0;
-}
-
 /* See if node has been suspiciously still for some time */
 int	may_be_dead(detector_state const ds, node_no i, double seconds)
 {
@@ -322,10 +302,8 @@ int	detector_task(task_arg arg MY_ATTRIBUTE((unused)))
 			DBGOHK(FN; NDBG(iamtheleader(x_site), d); NDBG(enough_live_nodes(x_site), d); );
 			/* Send xcom message if node has changed state */
 			DBGOHK(FN; NDBG(ep->notify,d));
-			if ((xcom_id_changed() || ep->notify) &&
-				enough_live_nodes(x_site) && iamtheleader(x_site)) {
+			if (ep->notify && iamtheleader(x_site) && enough_live_nodes(x_site)) {
 				ep->notify = 0;
-                reset_id_changed();
 				send_my_view(x_site);
 			}
 		}

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_detector.h

@@ -29,7 +29,6 @@ void note_detected(struct site_def const *site, node_no node);
 int	may_be_dead(detector_state const ds, node_no i, double seconds);
 void init_detector(detector_state ds);
 void invalidate_detector_sites(struct site_def *site);
-void update_xcom_id(node_no node, uint32_t id);
 
 #ifdef __cplusplus
 }

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_proto_enum.h

@@ -17,8 +17,7 @@ enum xcom_proto {
 	x_unknown_proto=0,
 	x_1_0=1,
 	x_1_1=2,
-	x_1_2=3,
-	x_1_3=4
+	x_1_2=3
 };
 
 typedef enum xcom_proto xcom_proto;

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_transport.c

@@ -54,7 +54,7 @@
 #include "xcom_ssl_transport.h"
 #endif
 
-#define MY_XCOM_PROTO x_1_3
+#define MY_XCOM_PROTO x_1_2
 
 xcom_proto const my_min_xcom_version = x_1_0; /* The minimum protocol version I am able to understand */
 xcom_proto const my_xcom_version = MY_XCOM_PROTO; /* The maximun protocol version I am able to understand */
@@ -658,20 +658,11 @@ static inline int old_proto_knows(xcom_proto x_proto MY_ATTRIBUTE((unused)),
 
 int serialize_msg(pax_msg *p, xcom_proto x_proto, uint32_t *buflen, char **buf)
 {
-	int retval = 0;
-
 	*buflen = 0;
 	*buf = 0;
 
-	if(old_proto_knows(x_proto, p->op)){
-	/* We want to send the internal xcom ID instead of the reference count,
-	so we need to save and restore the count */
-		int save = p->refcnt;
-		p->refcnt = (int) get_my_id();
-		retval =  serialize((void * )p, x_proto, buflen, (xdrproc_t)xdr_pax_msg, buf);
-		p->refcnt = save;
-	}
-	return retval;
+	return old_proto_knows(x_proto, p->op) &&
+						serialize((void *)p, x_proto, buflen, (xdrproc_t)xdr_pax_msg, buf);
 }
 
 int deserialize_msg(pax_msg *p, xcom_proto x_proto,  char *buf, uint32_t buflen)
@@ -2162,7 +2153,6 @@ bool_t xdr_node_list_1_1(XDR *xdrs, node_list_1_1 *objp)
 		sizeof (node_address), (xdrproc_t) xdr_node_address_with_1_0);
 	case x_1_1:
 	case x_1_2:
-	case x_1_3:
 		return xdr_array (xdrs, (char **)&objp->node_list_val, (u_int *) &objp->node_list_len, NSERVERS,
 		sizeof (node_address), (xdrproc_t) xdr_node_address);
 	default:
@@ -2195,7 +2185,6 @@ bool_t xdr_pax_msg(XDR *xdrs, pax_msg *objp)
 			objp->delivered_msg = get_delivered_msg(); /* Use our own minimum */
 		return TRUE;
 	case x_1_2:
-	case x_1_3:
 		return xdr_pax_msg_1_2(xdrs, objp);
 	default:
 		return FALSE;

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_vp.h.gen

@@ -34,8 +34,7 @@ enum xcom_proto {
 	x_unknown_proto = 0,
 	x_1_0 = 1,
 	x_1_1 = 2,
-	x_1_2 = 3,
-	x_1_3 = 4,
+	x_1_2 = 3
 };
 typedef enum xcom_proto xcom_proto;
 

rapid/plugin/group_replication/libmysqlgcs/src/bindings/xcom/xcom/xcom_vp_str.c

@@ -218,8 +218,6 @@ const char *xcom_proto_to_str(xcom_proto x)
         return "x_1_1";
     case x_1_2:
         return "x_1_2";
-    case x_1_3:
-        return "x_1_3";
     default:
         return "???";
     }