BUG#11809016 - NO WAY TO DISCOVER AN INSTANCE IS NO LONGER A SLAVE FOLLOWING MYSQL BUG#28796

Before BUG#28796, an empty host was used to identify that an instance was no
longer a slave. However, BUG#28796 changed this behavior and one cannot set
an empty host. Besides, a RESET SLAVE only cleans up information on the next
event to retrieve from the master, disables ssl and resets heartbeat period.
So a call to SHOW SLAVE STATUS after issuing a RESET SLAVE still returns some
valid information, such as host, port, user and password.

To fix this problem, we have introduced the command RESET SLAVE ALL that does
what a regular RESET SLAVE does and also clears host, port, user and password
information thus allowing users to identify when an instance is no longer a
slave.

5 files changed, 28 insertions, 4 deletions

diff --git a/sql/rpl_mi.cc b/sql/rpl_mi.cc
index d1fd6bac41c..0060bcb6b1e 100644
--- a/sql/rpl_mi.cc
+++ b/sql/rpl_mi.cc
@@ -31,6 +31,8 @@ int init_strvar_from_file(char *var, int max_size, IO_CACHE *f,
 int init_floatvar_from_file(float* var, IO_CACHE* f, float default_val);
 int init_dynarray_intvar_from_file(DYNAMIC_ARRAY* arr, IO_CACHE* f);
 
+static void init_master_log_pos(Master_info* mi);
+
 Master_info::Master_info(bool is_slave_recovery)
   :Slave_reporting_capability("I/O"),
    ssl(0), ssl_verify_server_cert(0), fd(-1), io_thd(0), 
@@ -100,6 +102,16 @@ bool Master_info::shall_ignore_server_id(ulong s_id)
       != NULL;
 }
 
+void Master_info::clear_in_memory_info(bool all)
+{
+  init_master_log_pos(this);
+  if (all)
+  {
+    port= MYSQL_PORT;
+    host[0] = 0; user[0] = 0; password[0] = 0;
+  }
+}
+
 void init_master_log_pos(Master_info* mi)
 {
   DBUG_ENTER("init_master_log_pos");
@@ -234,7 +246,7 @@ file '%s')", fname);
     }
 
     mi->fd = fd;
-    init_master_log_pos(mi);
+    mi->clear_in_memory_info(false);
 
   }
   else // file exists
diff --git a/sql/rpl_mi.h b/sql/rpl_mi.h
index 2e06d3e8b94..1434ba45519 100644
--- a/sql/rpl_mi.h
+++ b/sql/rpl_mi.h
@@ -62,6 +62,7 @@ class Master_info : public Slave_reporting_capability
   Master_info(bool is_slave_recovery);
   ~Master_info();
   bool shall_ignore_server_id(ulong s_id);
+  void clear_in_memory_info(bool all);
 
   /* the variables below are needed because we can change masters on the fly */
   char master_log_name[FN_REFLEN];
@@ -113,7 +114,6 @@ class Master_info : public Slave_reporting_capability
   DYNAMIC_ARRAY ignore_server_ids;
   ulong master_id;
 };
-void init_master_log_pos(Master_info* mi);
 int init_master_info(Master_info* mi, const char* master_info_fname,
 		     const char* slave_info_fname,
 		     bool abort_if_no_master_info_file,
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index accbd78246e..d3b0f578007 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -294,6 +294,10 @@ typedef struct st_lex_master_info
   DYNAMIC_ARRAY repl_ignore_server_ids;
 } LEX_MASTER_INFO;
 
+typedef struct st_lex_reset_slave
+{
+  bool all;
+} LEX_RESET_SLAVE;
 
 enum sub_select_type
 {
@@ -2232,6 +2236,7 @@ struct LEX: public Query_tables_list
   LEX_MASTER_INFO mi;				// used by CHANGE MASTER
   LEX_SERVER_OPTIONS server_options;
   USER_RESOURCES mqh;
+  LEX_RESET_SLAVE reset_slave_info;
   ulong type;
   /*
     This variable is used in post-parse stage to declare that sum-functions,
diff --git a/sql/sql_repl.cc b/sql/sql_repl.cc
index 001c4cec678..8653607263f 100644
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -1285,8 +1285,9 @@ int reset_slave(THD *thd, Master_info* mi)
     goto err;
   }
 
-  /* Clear master's log coordinates */
-  init_master_log_pos(mi);
+  /* Clear master's log coordinates and associated information */
+  mi->clear_in_memory_info(thd->lex->reset_slave_info.all);
+
   /*
      Reset errors (the idea is that we forget about the
      old master).
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 564250a9bf2..90a55471792 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -11337,10 +11337,16 @@ reset_options:
 
 reset_option:
           SLAVE               { Lex->type|= REFRESH_SLAVE; }
+          slave_reset_options { }
         | MASTER_SYM          { Lex->type|= REFRESH_MASTER; }
         | QUERY_SYM CACHE_SYM { Lex->type|= REFRESH_QUERY_CACHE;}
         ;
 
+slave_reset_options:
+          /* empty */ { Lex->reset_slave_info.all= false; }
+        | ALL         { Lex->reset_slave_info.all= true; }
+        ;
+
 purge:
           PURGE
           {