Merge ua141d10.elisa.omakaista.fi:/home/my/bk/mysql-4.1

into  ua141d10.elisa.omakaista.fi:/home/my/bk/mysql-5.0-tmp

1 files changed, 11 insertions, 13 deletions

diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index a8e21177338..620b9676dde 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -244,7 +244,7 @@ int mysql_update(THD *thd,
   }
   if (!select && limit != HA_POS_ERROR)
   {
-    if (MAX_KEY != (used_index= get_index_for_order(table, order, limit)))
+    if ((used_index= get_index_for_order(table, order, limit)) != MAX_KEY)
       need_sort= FALSE;
   }
   /* If running in safe sql mode, don't allow updates without keys */
@@ -267,14 +267,14 @@ int mysql_update(THD *thd,
     used_key_is_modified= (!select->quick->unique_key_range() &&
                           select->quick->check_if_keys_used(&fields));
   }
-  else if (used_index != MAX_KEY)
+  else
   {
-    used_key_is_modified= check_if_key_used(table, used_index, fields);
+    used_key_is_modified= 0;
+    if (used_index == MAX_KEY)                  // no index for sort order
+      used_index= table->file->key_used_on_scan;
+    if (used_index != MAX_KEY)
+      used_key_is_modified= check_if_key_used(table, used_index, fields);
   }
-  else if ((used_index=table->file->key_used_on_scan) < MAX_KEY)
-    used_key_is_modified=check_if_key_used(table, used_index, fields);
-  else
-    used_key_is_modified=0;
 
   if (used_key_is_modified || order)
   {
@@ -286,11 +286,11 @@ int mysql_update(THD *thd,
     if (used_index < MAX_KEY && old_used_keys.is_set(used_index))
     {
       table->key_read=1;
-      table->file->extra(HA_EXTRA_KEYREAD); //todo: psergey: check
+      table->file->extra(HA_EXTRA_KEYREAD);
     }
 
     /* note: can actually avoid sorting below.. */
-    if (order && need_sort)
+    if (order && (need_sort || used_key_is_modified))
     {
       /*
 	Doing an ORDER BY;  Let filesort find and sort the rows we are going
@@ -300,6 +300,7 @@ int mysql_update(THD *thd,
       SORT_FIELD  *sortorder;
       ha_rows examined_rows;
 
+      used_index= MAX_KEY;                   // For call to init_read_record()
       table->sort.io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
 						    MYF(MY_FAE | MY_ZEROFILL));
       if (!(sortorder=make_unireg_sortorder(order, &length)) ||
@@ -366,10 +367,7 @@ int mysql_update(THD *thd,
 	error= 1;				// Aborted
       limit= tmp_limit;
       end_read_record(&info);
-
-      /* if we got here we must not use index in the main update loop below */
-      used_index= MAX_KEY;
-      
+     
       /* Change select to use tempfile */
       if (select)
       {