Implementation of WL#1824 "Add replication of character set variables in 4.1",

by binlogging some SET ONE_SHOT CHARACTER_SETetc,
which will be enough until we have it more compact and more complete in 5.0. With the present patch,
replication will work ok between 4.1.3 master and slaves, as long as:
- master and slave have the same GLOBAL.COLLATION_SERVER
- COLLATION_DATABASE and CHARACTER_SET_DATABASE are not used
- application does not use the fact that table is created with charset of the USEd db (BUG#2326).
all of which are not too hard to fulfill. 
ONE_SHOT is reserved for internal use of mysqlbinlog|mysql and works only for charsets,
so we give error if used for non-charset vars.
Fix for BUG#3875 "mysqlbinlog produces wrong ouput  if query uses
 variables containing quotes" and BUG#3943 "Queries with non-ASCII literals are not replicated
 properly after SET NAMES".
Detecting that master and slave have different global charsets or server ids.


mysql-test/r/rpl_server_id1.result:
  it's normal to not run as I have added a test to compare server ids of master and slave
  at startup and stop if equal (unless --replicate-same-server-id)
mysql-test/r/rpl_user_variables.result:
  result update (as we now print charset of user var).
mysql-test/r/user_var.result:
  result update
mysql-test/t/rpl_server_id1.test:
  no need to select as slave is not running
mysql-test/t/user_var.test:
  testing if the content of user vars is escaped when mysqlbinlog prints them,
  and if the name is backquoted.
sql/lex.h:
  new keyword ONE_SHOT
sql/log.cc:
  when writing to the binlog, before writing the actual statement, write some SET ONE_SHOT CHARACTER_SET_CLIENT etc
  for the slave to know the charset variables (which are important as they affect the inserted data).
sql/log_event.cc:
  print charset and collation of user var in mysqlbinlog and SHOW BINLOG EVENTS.
  escape the content of the var. Backquote its name.
  Will ask Bar to check that using my_charset_bin for escaping is ok.
sql/set_var.cc:
  understand SET CHARACTER_SET_CLIENT=10 (don't require a string, accept a number).
  Refuse changing of GLOBAL CHARACTER_SET_SERVER/COLLATION_SERVER if binlog or slave,
  as it will make the master or slave make wrong assumptions.
  A function to catch SET ONE_SHOT on non-charset variables (which is forbidden)
sql/set_var.h:
  no_support_one_shot to know if the var supports ONE_SHOT (only charset vars do, soon timezones).
  Accept int arg in SET CHARACTER_SET_etc
sql/slave.cc:
  when I/O slave thread starts, verify that master's and slave charsets match.
  And by the way verify that server ids are different.
  Don't fail if UNIX_TIMESTAMP() can't be done on master (very old master), that's
  not fatal.
sql/sql_class.cc:
  one_shot
sql/sql_class.h:
  one_shot
sql/sql_lex.h:
  one_shot
sql/sql_parse.cc:
  when SET ONE_SHOT is used, verify that it's only used for charset/collation vars;
  otherwise refuse.
sql/sql_yacc.yy:
  ONE_SHOT keyword in SET

1 files changed, 47 insertions, 9 deletions

diff --git a/sql/set_var.h b/sql/set_var.h
index 699f320bbd9..64bdfdb718b 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -49,10 +49,20 @@ public:
   const char *name;
   
   sys_after_update_func after_update;
-  sys_var(const char *name_arg) :name(name_arg),after_update(0)
-  {}
+#if MYSQL_VERSION_ID < 50000
+  bool no_support_one_shot;
+#endif
+  sys_var(const char *name_arg)
+    :name(name_arg), after_update(0)
+#if MYSQL_VERSION_ID < 50000
+    , no_support_one_shot(1)
+#endif
+    {}
   sys_var(const char *name_arg,sys_after_update_func func)
-    :name(name_arg),after_update(func)
+    :name(name_arg), after_update(func)
+#if MYSQL_VERSION_ID < 50000
+    , no_support_one_shot(1)
+#endif
   {}
   virtual ~sys_var() {}
   virtual bool check(THD *thd, set_var *var);
@@ -487,12 +497,17 @@ public:
 class sys_var_collation :public sys_var_thd
 {
 public:
-  sys_var_collation(const char *name_arg) :sys_var_thd(name_arg) {}
+  sys_var_collation(const char *name_arg) :sys_var_thd(name_arg)
+    {
+#if MYSQL_VERSION_ID < 50000
+    no_support_one_shot= 0;
+#endif
+    }
   bool check(THD *thd, set_var *var);
 SHOW_TYPE type() { return SHOW_CHAR; }
   bool check_update_type(Item_result type)
   {
-    return type != STRING_RESULT;		/* Only accept strings */
+    return ((type != STRING_RESULT) && (type != INT_RESULT));
   }
   bool check_default(enum_var_type type) { return 0; }
   virtual void set_default(THD *thd, enum_var_type type)= 0;
@@ -502,13 +517,23 @@ class sys_var_character_set :public sys_var_thd
 {
 public:
   bool nullable;
-  sys_var_character_set(const char *name_arg) :sys_var_thd(name_arg) 
-  { nullable= 0; }
+  sys_var_character_set(const char *name_arg) :
+    sys_var_thd(name_arg)
+  {
+    nullable= 0;
+#if MYSQL_VERSION_ID < 50000
+    /*
+      In fact only almost all variables derived from sys_var_character_set
+      support ONE_SHOT; character_set_results doesn't. But that's good enough.
+    */
+    no_support_one_shot= 0;
+#endif
+  }
   bool check(THD *thd, set_var *var);
   SHOW_TYPE type() { return SHOW_CHAR; }
   bool check_update_type(Item_result type)
   {
-    return type != STRING_RESULT;		/* Only accept strings */
+    return ((type != STRING_RESULT) && (type != INT_RESULT));
   }
   bool check_default(enum_var_type type) { return 0; }
   bool update(THD *thd, set_var *var);
@@ -541,6 +566,9 @@ class sys_var_character_set_server :public sys_var_character_set
 public:
   sys_var_character_set_server(const char *name_arg) :
     sys_var_character_set(name_arg) {}
+#if defined(HAVE_REPLICATION) && (MYSQL_VERSION_ID < 50000)
+  bool check(THD *thd, set_var *var);
+#endif
   void set_default(THD *thd, enum_var_type type);
   CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
 };
@@ -576,6 +604,9 @@ class sys_var_collation_server :public sys_var_collation
 {
 public:
   sys_var_collation_server(const char *name_arg) :sys_var_collation(name_arg) {}
+#if defined(HAVE_REPLICATION) && (MYSQL_VERSION_ID < 50000)
+  bool check(THD *thd, set_var *var);
+#endif
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
@@ -689,7 +720,10 @@ public:
   virtual int check(THD *thd)=0;	/* To check privileges etc. */
   virtual int update(THD *thd)=0;	/* To set the value */
   /* light check for PS */
-  virtual   int light_check(THD *thd) { return check(thd); }
+  virtual int light_check(THD *thd) { return check(thd); }
+#if MYSQL_VERSION_ID < 50000
+  virtual bool no_support_one_shot() { return 1; }
+#endif
 };
 
 
@@ -731,6 +765,9 @@ public:
   int check(THD *thd);
   int update(THD *thd);
   int light_check(THD *thd);
+#if MYSQL_VERSION_ID < 50000
+  bool no_support_one_shot() { return var->no_support_one_shot; }
+#endif
 };
 
 
@@ -833,6 +870,7 @@ void set_var_init();
 void set_var_free();
 sys_var *find_sys_var(const char *str, uint length=0);
 int sql_set_variables(THD *thd, List<set_var_base> *var_list);
+bool not_all_support_one_shot(List<set_var_base> *var_list);
 void fix_delay_key_write(THD *thd, enum_var_type type);
 ulong fix_sql_mode(ulong sql_mode);
 extern sys_var_str sys_charset_system;