Fix bug in SELECT EXPLAIN ... ORDER BY

Docs/internals.texi

@@ -214,12 +214,15 @@ you will not develop sloppy coding habits.
 If you can write it in fewer lines, do it (as long as the code will not
 be slower or much harder to read).
 
+@item
+Don't use two commands on the same line.
+
 @item
 Do not check the same pointer for @code{NULL} more than once.
 
 @item
-Use long function and variable names in English;  This makes your
-code easier to read.
+Use long function and variable names in English; This makes your code
+easier to read.  Use the 'varible_name' style instead of 'VariableName'.
 
 @item
 Think assembly - make it easier for the compiler to optimize your code.
@@ -266,6 +269,25 @@ Any @code{#define}'s are in all-caps.
 @item
 Matching @samp{@{} are in the same column.
 
+@item
+Put the @samp{@{} after a 'switch' on the same line
+
+@example
+switch (arg) {
+@end example
+
+Because this gives better overall indentation for the switch statement.
+
+@item
+In all other cases, @{ and @} should be on their own line, except
+if there is nothing inside @{ @}.
+
+@item
+Have a space after 'if'
+
+@item
+Put a space after ',' for function arguments
+
 @item
 Functions return 0 on success, and non-zero on error, so you can do:
 
@@ -289,6 +311,32 @@ Use pointers rather than array indexing when operating on strings.
 
 @end itemize
 
+Suggested mode in emacs:
+
+@example
+(load "cc-mode")
+(setq c-mode-common-hook '(lambda ()
+			    (turn-on-font-lock)
+			    (setq comment-column 48)))
+(setq c-style-alist
+      (cons
+       '("MY"
+	 (c-basic-offset . 2)
+	 (c-comment-only-line-offset . 0)
+	 (c-offsets-alist . ((statement-block-intro . +)
+			     (knr-argdecl-intro . 0)
+			     (substatement-open . 0)
+			     (label . -)
+			     (statement-cont . +)
+			     (arglist-intro . c-lineup-arglist-intro-after-paren)
+			     (arglist-close . c-lineup-arglist)
+			     ))
+	 )
+       c-style-alist))
+(c-set-style "MY")
+(setq c-default-style "MY")
+@end example
+
 @node mysys functions,,,
 @chapter mysys functions
 

Docs/manual.texi

@@ -46853,6 +46853,9 @@ not yet 100% confident in this code.
 @appendixsubsec Changes in release 3.23.43
 @itemize @bullet
 @item
+Fixed a unlikely core-dump bug when doing @code{EXPLAIN SELECT} when using
+many tables and @code{ORDER BY}.
+@item
 Fixed bug in @code{LOAD DATA FROM MASTER} when using table with
 @code{CHECKSUM=1}.
 @item

myisam/mi_check.c

@@ -1291,11 +1291,8 @@ int mi_repair(MI_CHECK *param, register MI_INFO *info,
   {
     info->state->data_file_length=sort_info->max_pos;
     if (param->testflag & T_CALC_CHECKSUM)
-    {
-      DBUG_PRINT("QQ",("set_checksum"));
       share->state.checksum=param->glob_crc;
   }
-  }
 
   if (!(param->testflag & T_SILENT))
   {
@@ -2136,10 +2133,7 @@ static int sort_get_next_record(SORT_INFO *sort_info)
       if (*sort_info->record)
       {
 	if (param->calc_checksum)
-	{
-	  DBUG_PRINT("QQ",("calc_checksum"));
 	  param->glob_crc+= mi_static_checksum(info,sort_info->record);
-	}
 	DBUG_RETURN(0);
       }
       if (!sort_info->fix_datafile)

sql/sql_select.cc

@@ -531,8 +531,9 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
 
   if (!(select_options & SELECT_BIG_RESULT) &&
       ((group && join.const_tables != join.tables &&
+	(!simple_group ||
 	 !test_if_skip_sort_order(&join.join_tab[join.const_tables], group,
-				 HA_POS_ERROR)) ||
+				  HA_POS_ERROR))) ||
        select_distinct) &&
       join.tmp_table_param.quick_group && !procedure)
   {
@@ -545,8 +546,10 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
       order=group;
     if (order &&
 	(join.const_tables == join.tables ||
+	 (simple_order &&
 	  test_if_skip_sort_order(&join.join_tab[join.const_tables], order,
-				 (group ? HA_POS_ERROR : thd->select_limit))))
+				  (group ? HA_POS_ERROR :
+				   thd->select_limit)))))
       order=0;
     select_describe(&join,need_tmp,
 		    (order != 0 &&