Fix for bug #28837: MyISAM storage engine error (134) doing delete with

self-join

When doing DELETE with self-join on a MyISAM or MERGE table, it could
happen that a record being retrieved in join_read_next_same() has
already been deleted by previous iterations. That caused the engine's
index_next_same() method to fail with HA_ERR_RECORD_DELETED error and
the whole DELETE query to be aborted with an error.

Fixed by suppressing the HA_ERR_RECORD_DELETED error in
hy_myisam::index_next_same() and ha_myisammrg::index_next_same(). Since
HA_ERR_RECORD_DELETED can only be returned by MyISAM, there is no point
in filtering this error in the SQL layer.


mysql-test/r/merge.result:
  Added a test case for bug #28837.
mysql-test/r/myisam.result:
  Added a test case for bug #28837.
mysql-test/t/merge.test:
  Added a test case for bug #28837.
mysql-test/t/myisam.test:
  Added a test case for bug #28837.
sql/ha_myisam.cc:
  Skip HA_ERR_RECORD_DELETED silently when calling mi_rnext_same().
sql/ha_myisammrg.cc:
  Skip HA_ERR_RECORD_DELETED silently when calling mi_rnext_same().

1 files changed, 6 insertions, 2 deletions

diff --git a/sql/ha_myisam.cc b/sql/ha_myisam.cc
index 92fa9e405e1..86f04672676 100644
--- a/sql/ha_myisam.cc
+++ b/sql/ha_myisam.cc
@@ -1602,10 +1602,14 @@ int ha_myisam::index_next_same(byte * buf,
 			       const byte *key __attribute__((unused)),
 			       uint length __attribute__((unused)))
 {
+  int error;
   DBUG_ASSERT(inited==INDEX);
   statistic_increment(table->in_use->status_var.ha_read_next_count,
-		      &LOCK_status);
-  int error=mi_rnext_same(file,buf);
+                      &LOCK_status);
+  do
+  {
+    error= mi_rnext_same(file,buf);
+  } while (error == HA_ERR_RECORD_DELETED);
   table->status=error ? STATUS_NOT_FOUND: 0;
   return error;
 }