Fixes bug when we run bcmp() on row when the storage engine hasn't filled in all fields in the row.

This was triggered by innodb.innodb_multi_update, where we had a static length row without nulls and xtradb didn't fill in the delete-marker byte


include/my_bitmap.h:
  Added prototype for bitmap_union_is_set_all()
mysys/my_bitmap.c:
  Added function to check if union of two bit maps covers all bits.
sql/mysql_priv.h:
  Updated protype for compare_record()
sql/sql_insert.cc:
  Send to compare_record() flag if all fields are used.
sql/sql_select.cc:
  Set share->null_bytes_for_compare.
sql/sql_update.cc:
  In compare_record() don't use the fast cmp_record() (which is basically memcmp) if we don't know that all fields exists.
  Don't compare the null_bytes if there is no data there.
sql/table.cc:
  Store in share->null_bytes_for_compare the number of bytes that has null or bit fields (but not delete marker)
  Store in can_cmp_whole_record if we can use memcmp() (assuming all rows are read) to compare rows in compare_record()
sql/table.h:
  Added two elements in table->share to speed up checking how updated rows can be compared.

1 files changed, 18 insertions, 0 deletions

diff --git a/mysys/my_bitmap.c b/mysys/my_bitmap.c
index 137127a2fda..69e0ca18cb8 100644
--- a/mysys/my_bitmap.c
+++ b/mysys/my_bitmap.c
@@ -378,6 +378,24 @@ void bitmap_intersect(MY_BITMAP *map, const MY_BITMAP *map2)
   }
 }
 
+/* True if union of bitmaps have all bits set */
+
+my_bool bitmap_union_is_set_all(const MY_BITMAP *map1, const MY_BITMAP *map2)
+{
+  my_bitmap_map *m1= map1->bitmap, *m2= map2->bitmap, *end;
+
+  DBUG_ASSERT(map1->bitmap && map2->bitmap &&
+              map1->n_bits==map2->n_bits);
+  *map1->last_word_ptr|= map1->last_word_mask;
+
+  end= map1->last_word_ptr;
+  while ( m1 <= end)
+    if ((*m1++ | *m2++) != 0xFFFFFFFF)
+      return FALSE;
+  return TRUE;
+}
+
+
 
 /*
   Set/clear all bits above a bit.