Merge Bug#54686 fix from mysql-5.1-innodb:

------------------------------------------------------------
revno: 3517
revision-id: marko.makela@oracle.com-20100622115215-kxtzx7xuugcxd375
parent: marko.makela@oracle.com-20100621095148-8g73k8k68dpj080u
committer: Marko Mäkelä <marko.makela@oracle.com>
branch nick: 5.1-innodb
timestamp: Tue 2010-06-22 14:52:15 +0300
message:
  Bug#54686 "field->col->mtype == type" assertion error at row/row0sel.c
  ha_innobase::index_read(), ha_innobase::records_in_range(): Check that
  the index is useable before invoking row_sel_convert_mysql_key_to_innobase().

  This fix is based on a suggestion by Yasufumi Kinoshita.

storage/innobase/handler/ha_innodb.cc

@@ -5568,6 +5568,9 @@ ha_innobase::index_read(
 		prebuilt->index_usable = FALSE;
 		DBUG_RETURN(HA_ERR_CRASHED);
 	}
+	if (UNIV_UNLIKELY(!prebuilt->index_usable)) {
+		DBUG_RETURN(HA_ERR_TABLE_DEF_CHANGED);
+	}
 
 	/* Note that if the index for which the search template is built is not
 	necessarily prebuilt->index, but can also be the clustered index */
@@ -7410,6 +7413,10 @@ ha_innobase::records_in_range(
 		n_rows = HA_POS_ERROR;
 		goto func_exit;
 	}
+	if (UNIV_UNLIKELY(!row_merge_is_index_usable(prebuilt->trx, index))) {
+		n_rows = HA_ERR_TABLE_DEF_CHANGED;
+		goto func_exit;
+	}
 
 	heap = mem_heap_create(2 * (key->key_parts * sizeof(dfield_t)
 				    + sizeof(dtuple_t)));