Bug#4521: unique key prefix interacts poorly with utf8.

Fix for binary collations for MyISAM and HEAP BTREE.
This patch also changes trailing spaces behaviour for
binary collations. Binary collations now have PAD 
characteristic too.

1 files changed, 12 insertions, 3 deletions

diff --git a/myisam/mi_search.c b/myisam/mi_search.c
index 2f1c37e4f21..24f5db1401d 100644
--- a/myisam/mi_search.c
+++ b/myisam/mi_search.c
@@ -396,9 +396,18 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
 
       matched=prefix_len+left;
 
-      for (my_flag=0;left;left--)
-        if ((my_flag= (int) sort_order[*vseg++] - (int) sort_order[*k++]))
-          break;
+      if (sort_order)
+      {
+        for (my_flag=0;left;left--)
+          if ((my_flag= (int) sort_order[*vseg++] - (int) sort_order[*k++]))
+            break;
+      }
+      else
+      {
+        for (my_flag=0;left;left--)
+          if ((my_flag= (int) *vseg++ - (int) *k++))
+            break;
+      }
 
       if (my_flag>0)      /* mismatch */
         break;