bk commit into 4.1 tree (gkodinov:1.2522) BUG#17212

[kgeorge]

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ChangeSet@stripped, 2006-07-07 18:08:33+03:00, gkodinov@stripped +1 -0
  Bug #17212 results not sorted correctly by ORDER BY when using index
    * opt not to use join cache in favor of using index for ORDER BY.
      This choise must be made because join cache will effectively 
      reverse the join order and the results will no longer be sorted
      by the index of the left table.

  sql/sql_select.cc@stripped, 2006-07-07 18:08:26+03:00, gkodinov@stripped +8 -1
    Bug #17212 results not sorted correctly by ORDER BY when using index
      * don't use join cache when using index for sorting

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	gkodinov
# Host:	macbook.gmz
# Root:	/Users/kgeorge/mysql/4.1/B17212

--- 1.457/sql/sql_select.cc	2006-07-07 18:08:44 +03:00
+++ 1.458/sql/sql_select.cc	2006-07-07 18:08:44 +03:00
@@ -3924,10 +3924,17 @@
     case JT_ALL:
       /*
 	If previous table use cache
+        Note: if the previous table is using index for sorting
+        don't use cache.
       */
       table->status=STATUS_NO_RECORD;
       if (i != join->const_tables && !(options & SELECT_NO_JOIN_CACHE)
&&
-	  tab->use_quick != 2 && !tab->on_expr)
+	  tab->use_quick != 2 && !tab->on_expr &&
+          !(i == join->const_tables + 1 &&
+            join->sort_by_table == join->join_tab[i - 1].table &&
+            (!join->order || join->skip_sort_order ||
+             test_if_skip_sort_order(&join->join_tab[i - 1], 
+                                     join->order, join->select_limit, 1))))
       {
 	if ((options & SELECT_DESCRIBE) ||
 	    !join_init_cache(join->thd,join->join_tab+join->const_tables,