Fix for bug#35383: binlog playback and replication breaks

due to name_const substitution

Problem:
"In general, statements executed within a stored procedure
are written to the binary log using the same rules that
would apply were the statements to be executed in standalone
fashion. Some special care is taken when logging procedure
statements because statement execution within procedures
is not quite the same as in non-procedure context".

For example, each reference to a local variable in SP's
statements is replaced by NAME_CONST(var_name, var_value).
Queries like
"CREATE TABLE ... SELECT FUNC(local_var ..."
are logged as
"CREATE TABLE ... SELECT FUNC(NAME_CONST("local_var", var_value) ..."
that leads to differrent field names and
might result in "Incorrect column name" if var_value is long enough.

Fix: in 5.x we'll issue a warning in such a case.
In 6.0 we should get rid of NAME_CONST().

Note: this issue and change should be described in the documentation
("Binary Logging of Stored Programs").


mysql-test/r/binlog.result:
  Fix for bug#35383: binlog playback and replication breaks
  due to name_const substitution
    - test result.
mysql-test/t/binlog.test:
  Fix for bug#35383: binlog playback and replication breaks
  due to name_const substitution
    - test case.
sql/sp_head.cc:
  Fix for bug#35383: binlog playback and replication breaks 
  due to name_const substitution
    - set thd->query_name_consts if there's NAME_CONST()
  substitution(s).
sql/sql_parse.cc:
  Fix for bug#35383: binlog playback and replication breaks 
  due to name_const substitution
    - issue a warning if there's NAME_CONST() substitution and
  binary logging is on for "CREATE TABLE ... SELECT ...".

4 files changed, 45 insertions, 0 deletions

diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index b51d97e66c5..76b0f2e22d2 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -894,6 +894,8 @@ subst_spvars(THD *thd, sp_instr *instr, LEX_STRING *query_str)
   qbuf.length(0);
   cur= query_str->str;
   prev_pos= res= 0;
+  thd->query_name_consts= 0;
+  
   for (Item_splocal **splocal= sp_vars_uses.front(); 
        splocal < sp_vars_uses.back(); splocal++)
   {
@@ -927,6 +929,8 @@ subst_spvars(THD *thd, sp_instr *instr, LEX_STRING *query_str)
     res|= qbuf.append(')');
     if (res)
       break;
+      
+    thd->query_name_consts++;
   }
   res|= qbuf.append(cur + prev_pos, query_str->length - prev_pos);
   if (res)
@@ -2621,6 +2625,7 @@ sp_instr_stmt::execute(THD *thd, uint *nextp)
       *nextp= m_ip+1;
     thd->query= query;
     thd->query_length= query_length;
+    thd->query_name_consts= 0;
   }
   DBUG_RETURN(res);
 }
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 74bc669a049..07172dde549 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -219,6 +219,7 @@ THD::THD()
   one_shot_set= 0;
   file_id = 0;
   query_id= 0;
+  query_name_consts= 0;
   warn_id= 0;
   db_charset= global_system_variables.collation_database;
   bzero(ha_data, sizeof(ha_data));
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 3e3dfcd08fa..8a69e3729f2 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -1556,6 +1556,9 @@ public:
   sp_cache   *sp_proc_cache;
   sp_cache   *sp_func_cache;
 
+  /** number of name_const() substitutions, see sp_head.cc:subst_spvars() */
+  uint       query_name_consts;
+
   /*
     If we do a purge of binary logs, log index info of the threads
     that are currently reading it needs to be adjusted. To do that
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 33adcfe3342..4cfb41dbc76 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -3211,6 +3211,42 @@ mysql_execute_command(THD *thd)
     }
     if (select_lex->item_list.elements)		// With select
     {
+      /*
+        If:
+        a) we inside an SP and there was NAME_CONST substitution,
+        b) binlogging is on,
+        c) we log the SP as separate statements
+        raise a warning, as it may cause problems
+        (see 'NAME_CONST issues' in 'Binary Logging of Stored Programs')
+       */
+      if (thd->query_name_consts && 
+          mysql_bin_log.is_open() &&
+          !mysql_bin_log.is_query_in_union(thd, thd->query_id))
+      {
+        List_iterator_fast<Item> it(select_lex->item_list);
+        Item *item;
+        uint splocal_refs= 0;
+        /* Count SP local vars in the top-level SELECT list */
+        while ((item= it++))
+        {
+          if (item->is_splocal())
+            splocal_refs++;
+        }
+        /*
+          If it differs from number of NAME_CONST substitution applied,
+          we may have a SOME_FUNC(NAME_CONST()) in the SELECT list,
+          that may cause a problem with binary log (see BUG#35383),
+          raise a warning. 
+        */
+        if (splocal_refs != thd->query_name_consts)
+          push_warning(thd, 
+                       MYSQL_ERROR::WARN_LEVEL_WARN,
+                       ER_UNKNOWN_ERROR,
+"Invoked routine ran a statement that may cause problems with "
+"binary log, see 'NAME_CONST issues' in 'Binary Logging of Stored Programs' "
+"section of the manual.");
+      }
+      
       select_result *sel_result;
 
       select_lex->options|= SELECT_NO_UNLOCK;