Fix bug in SELECT EXPLAIN ... ORDER BY

Docs/internals.texi:
  Added more code style suggestions.
Docs/manual.texi:
  Changelog
myisam/mi_check.c:
  Removed dbug info

4 files changed, 60 insertions, 12 deletions

diff --git a/Docs/internals.texi b/Docs/internals.texi
index e0574df550b..2195b42d9a0 100644
--- a/Docs/internals.texi
+++ b/Docs/internals.texi
@@ -215,11 +215,14 @@ 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.
@@ -267,6 +270,25 @@ Any @code{#define}'s are in all-caps.
 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:
 
 @example
@@ -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
 
diff --git a/Docs/manual.texi b/Docs/manual.texi
index 9cf7f74feff..6dd44a79288 100644
--- a/Docs/manual.texi
+++ b/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
diff --git a/myisam/mi_check.c b/myisam/mi_check.c
index c4f37511ffa..fa4687e27f5 100644
--- a/myisam/mi_check.c
+++ b/myisam/mi_check.c
@@ -1291,10 +1291,7 @@ 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)
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index b6c261d1463..56ba4baed30 100644
--- a/sql/sql_select.cc
+++ b/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 &&
-	!test_if_skip_sort_order(&join.join_tab[join.const_tables], group,
-				 HA_POS_ERROR)) ||
+	(!simple_group ||
+	 !test_if_skip_sort_order(&join.join_tab[join.const_tables], group,
+				  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 ||
-	 test_if_skip_sort_order(&join.join_tab[join.const_tables], order,
-				 (group ? HA_POS_ERROR : thd->select_limit))))
+	 (simple_order &&
+	  test_if_skip_sort_order(&join.join_tab[join.const_tables], order,
+				  (group ? HA_POS_ERROR :
+				   thd->select_limit)))))
       order=0;
     select_describe(&join,need_tmp,
 		    (order != 0 &&