Bug#13963 SHOW SLAVE HOSTS is unreliable

      
      Before the patch, slaves only appear in the output of SHOW SLAVE HOSTS 
      when report-host option is set. If an expected slave does not appear in  
      the list, nobody knows whether the slave does not connect or has started
      without the "report-host" option. The output also contains a strange  
      field "Rpl_recovery_rank" which has never been implemented and the manual 
      of MySQL5.4 declares that the field has been removed from MySQL5.4.
                                        
      This patch is done with these,
      According to the manual of MySQL5.4, "Rpl_recovery_rank" is removed.
      Slaves will register themselves to master no matter if report_host option is set
      or not. When slaves are registering themselves, their Server_ids, report_host
      and other information are together sent to master. Sever_ids are never null 
      and is unique in one replication group. Slaves always can be identified with  
      different Server_ids no matter if report_host exists.

mysql-test/include/wait_show_condition.inc

@@ -2,13 +2,16 @@
 #
 # SUMMARY
 #
-#    Waits until the show statement ($show_statement) has at least within one of
-#    the rows of the result set for the field ($field) a value which fulfils
+#    Waits until the show statement ($show_statement) has one or all of the
+#    rows of the result set for the field ($field) a value which fulfils
 #    a condition ($condition), or the operation times out.
 #    
 #
 # USAGE
 #
+#    All rows of the result must fulfil the condition if $all_rows_fulfil is 1
+#    else at least one of the result must fulfil the condition.
+#    let $wait_for_all= 1; 
 #    let $show_statement= SHOW PROCESSLIST;
 #    let $field= State;
 #    let $condition= = 'Updating';
@@ -46,27 +49,56 @@ inc $max_run_time;
 
 let $found= 0;
 let $max_end_time= `SELECT UNIX_TIMESTAMP() + $max_run_time`;
-while (`SELECT UNIX_TIMESTAMP() <= $max_end_time AND $found = 0`)
+
+if (`SELECT '$wait_for_all' != '1'`)
 {
-   # Sleep a bit to avoid too heavy load.
-   real_sleep 0.2;
-   let $rowno= 1;
-   let $process_result= 1;
-   while (`SELECT $process_result = 1 AND $found = 0`)
-   {
-      let $field_value= query_get_value($show_statement, $field, $rowno);
-      if (`SELECT '$field_value' $condition`)
-      {
-         let $found= 1;
-      }
-      if (`SELECT '$field_value' = 'No such row'`)
-      {
-         # We are behind the last row of the result set.
-         let $process_result= 0;
-      }
-      inc $rowno;
-   }
+  while (`SELECT UNIX_TIMESTAMP() <= $max_end_time AND $found = 0`)
+  {
+     # Sleep a bit to avoid too heavy load.
+     real_sleep 0.2;
+     let $rowno= 1;
+     let $process_result= 1;
+     while (`SELECT $process_result = 1 AND $found = 0`)
+     {
+        let $field_value= query_get_value($show_statement, $field, $rowno);
+        if (`SELECT '$field_value' $condition`)
+        {
+           let $found= 1;
+        }
+        if (`SELECT '$field_value' = 'No such row'`)
+        {
+           # We are behind the last row of the result set.
+           let $process_result= 0;
+        }
+        inc $rowno;
+     }
+  }
 }
+
+if (`SELECT '$wait_for_all' = '1'`)
+{
+  while (`SELECT UNIX_TIMESTAMP() <= $max_end_time AND $found = 0`)
+  {
+     # Sleep a bit to avoid too heavy load.
+     real_sleep 0.2;
+     let $rowno= 1;
+     let $process_result= 1;
+     while (`SELECT $process_result = 1 AND $found = 0`)
+     {
+        let $field_value= query_get_value($show_statement, $field, $rowno);
+        if (`SELECT '$field_value' = 'No such row'`)
+        {
+           let $found= 1;
+        }
+        if (`SELECT $found = 0 AND NOT '$field_value' $condition`)
+        {
+           let process_result= 0;
+        }
+        inc $rowno;
+     }
+  }
+}
+
 if (!$found)
 {
   echo # Timeout in include/wait_show_condition.inc for $wait_condition;

mysql-test/suite/rpl/r/rpl_mixed_ddl_dml.result

@@ -13,8 +13,8 @@ n
 2001
 2002
 show slave hosts;
-Server_id	Host	Port	Rpl_recovery_rank	Master_id
-2	127.0.0.1	9999	0	1
+Server_id	Host	Port	Master_id
+2	127.0.0.1	9999	1
 drop table t1;
 stop slave;
 create table t2(id int auto_increment primary key, created datetime);

mysql-test/suite/rpl/r/rpl_show_slave_hosts.result

+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+RESET SLAVE;
+CHANGE MASTER TO master_host='127.0.0.1',master_port=13000,master_user='root';
+START SLAVE IO_THREAD;
+SHOW SLAVE HOSTS;
+Server_id	Host	Port	Master_id
+3	slave2	3306	1
+2		13001	1
+STOP SLAVE IO_THREAD;
+SHOW SLAVE HOSTS;
+Server_id	Host	Port	Master_id
+2		13001	1

mysql-test/suite/rpl/t/rpl_show_slave_hosts.cnf

+!include ../my.cnf
+
+[mysqld.1]
+server_id=1
+
+[mysqld.2]
+server_id=2
+report-host=
+report-user=
+
+[mysqld.3]
+server_id=3
+report-host=slave2
+slave-net-timeout=5
+
+[ENV]
+SLAVE_MYPORT2=		@mysqld.3.port
+SLAVE_MYSOCK2=		@mysqld.3.socket
+
+

mysql-test/suite/rpl/t/rpl_show_slave_hosts.test

+###############################################################################
+# Bug#13963 SHOW SLAVE HOSTS is unreliable
+#
+# Slaves only appear in the output of SHOW SLAVE HOSTS when report-host option
+# is set. If an expected slave does not appear in the list, nobody knows
+# whether the slave does not connect or has started without the "report-host"
+# option.
+#
+# Remove the "Rpl_recovery_rank" column from SHOW SLAVE HOSTS, It is not
+# implemented.
+#######################################################################
+source include/master-slave.inc;
+connect (slave2,127.0.0.1,root,,test,$SLAVE_MYPORT2,);
+
+connection slave2;
+RESET SLAVE;
+--eval CHANGE MASTER TO master_host='127.0.0.1',master_port=$MASTER_MYPORT,master_user='root'
+START SLAVE IO_THREAD;
+source include/wait_for_slave_io_to_start.inc;
+
+connection master;
+let $show_statement= SHOW SLAVE HOSTS;
+let $field= Server_id;
+# 3 is server_id of slave2.
+let $connection= ='3';
+source include/wait_show_condition.inc;
+SHOW SLAVE HOSTS;
+
+connection slave2;
+STOP SLAVE IO_THREAD;
+source include/wait_for_slave_io_to_stop.inc;
+
+connection master;
+let $show_statement= SHOW SLAVE HOSTS;
+let $field= Server_id;
+# 3 is server_id of slave2.
+let $condition= <> '3';
+# All rows of 'SHOW SLAVE HOSTS' are not equal to 3.  It mean that master has
+# knew the leave of slave2 and has unregistered it.
+let $wait_for_all= 1;
+source include/wait_show_condition.inc;
+SHOW SLAVE HOSTS;
+
+source include/master-slave-end.inc;

sql/repl_failsafe.cc

@@ -183,12 +183,11 @@ int register_slave(THD* thd, uchar* packet, uint packet_length)
   get_object(p,si->host, "Failed to register slave: too long 'report-host'");
   get_object(p,si->user, "Failed to register slave: too long 'report-user'");
   get_object(p,si->password, "Failed to register slave; too long 'report-password'");
-  if (p+10 > p_end)
+  /*6 is the total length of port and master_id*/
+  if (p+6 != p_end)
     goto err;
   si->port= uint2korr(p);
   p += 2;
-  si->rpl_recovery_rank= uint4korr(p);
-  p += 4;
   if (!(si->master_id= uint4korr(p)))
     si->master_id= server_id;
   si->thd= thd;
@@ -669,8 +668,6 @@ bool show_slave_hosts(THD* thd)
     field_list.push_back(new Item_empty_string("Password",20));
   }
   field_list.push_back(new Item_return_int("Port", 7, MYSQL_TYPE_LONG));
-  field_list.push_back(new Item_return_int("Rpl_recovery_rank", 7,
-					   MYSQL_TYPE_LONG));
   field_list.push_back(new Item_return_int("Master_id", 10,
 					   MYSQL_TYPE_LONG));
 
@@ -692,7 +689,6 @@ bool show_slave_hosts(THD* thd)
       protocol->store(si->password, &my_charset_bin);
     }
     protocol->store((uint32) si->port);
-    protocol->store((uint32) si->rpl_recovery_rank);
     protocol->store((uint32) si->master_id);
     if (protocol->write())
     {

sql/slave.cc

@@ -1745,28 +1745,48 @@ int register_slave_on_master(MYSQL* mysql, Master_info *mi,
                              bool *suppress_warnings)
 {
   uchar buf[1024], *pos= buf;
-  uint report_host_len, report_user_len=0, report_password_len=0;
+  uint report_host_len=0, report_user_len=0, report_password_len=0;
   DBUG_ENTER("register_slave_on_master");
 
   *suppress_warnings= FALSE;
-  if (!report_host)
+  if (report_host)
+    report_host_len= strlen(report_host);
+  if (report_host_len > HOSTNAME_LENGTH)
+  {
+    sql_print_warning("The length of report_host is %d. "
+                      "It is larger than the max length(%d), so this "
+                      "slave cannot be registered to the master.",
+                      report_host_len, HOSTNAME_LENGTH);
     DBUG_RETURN(0);
-  report_host_len= strlen(report_host);
+  }
+
   if (report_user)
     report_user_len= strlen(report_user);
+  if (report_user_len > USERNAME_LENGTH)
+  {
+    sql_print_warning("The length of report_user is %d. "
+                      "It is larger than the max length(%d), so this "
+                      "slave cannot be registered to the master.",
+                      report_user_len, USERNAME_LENGTH);
+    DBUG_RETURN(0);
+  }
+
   if (report_password)
     report_password_len= strlen(report_password);
-  /* 30 is a good safety margin */
-  if (report_host_len + report_user_len + report_password_len + 30 >
-      sizeof(buf))
-    DBUG_RETURN(0);                                     // safety
+  if (report_password_len > MAX_PASSWORD_LENGTH)
+  {
+    sql_print_warning("The length of report_password is %d. "
+                      "It is larger than the max length(%d), so this "
+                      "slave cannot be registered to the master.",
+                      report_password_len, MAX_PASSWORD_LENGTH);
+    DBUG_RETURN(0);
+  }
 
   int4store(pos, server_id); pos+= 4;
   pos= net_store_data(pos, (uchar*) report_host, report_host_len);
   pos= net_store_data(pos, (uchar*) report_user, report_user_len);
   pos= net_store_data(pos, (uchar*) report_password, report_password_len);
   int2store(pos, (uint16) report_port); pos+= 2;
-  int4store(pos, rpl_recovery_rank);    pos+= 4;
   /* The master will fill in master_id */
   int4store(pos, 0);                    pos+= 4;