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().

mysql-test/r/merge.result

@@ -876,4 +876,41 @@ CHECK TABLE tm1;
 Table	Op	Msg_type	Msg_text
 test.tm1	check	status	OK
 DROP TABLE tm1, t1, t2;
+CREATE TABLE t1 (id INT NOT NULL, ref INT NOT NULL, INDEX (id)) ENGINE=MyISAM;
+CREATE TABLE t2 LIKE t1;
+INSERT INTO t2 (id, ref) VALUES (1,3), (2,1), (3,2), (4,5), (4,4);
+INSERT INTO t1 SELECT * FROM t2;
+INSERT INTO t1 SELECT * FROM t2;
+CREATE TABLE t3 (id INT NOT NULL, ref INT NOT NULL, INDEX (id)) ENGINE=MERGE
+UNION(t1);
+SELECT * FROM t3 AS a INNER JOIN t3 AS b USING (id) WHERE a.ref < b.ref;
+id	ref	ref
+4	4	5
+4	4	5
+4	4	5
+4	4	5
+SELECT * FROM t3;
+id	ref
+1	3
+2	1
+3	2
+4	5
+4	4
+1	3
+2	1
+3	2
+4	5
+4	4
+DELETE FROM a USING t3 AS a INNER JOIN t3 AS b USING (id) WHERE a.ref < b.ref;
+SELECT * FROM t3;
+id	ref
+1	3
+2	1
+3	2
+4	5
+1	3
+2	1
+3	2
+4	5
+DROP TABLE t1, t2, t3;
 End of 5.0 tests

mysql-test/r/myisam.result

@@ -1806,4 +1806,26 @@ SELECT a FROM t1 FORCE INDEX (inx) WHERE a=1;
 a
 1
 DROP TABLE t1;
+CREATE TABLE t1 (id int NOT NULL, ref int NOT NULL, INDEX (id)) ENGINE=MyISAM;
+CREATE TABLE t2 LIKE t1;
+INSERT INTO t2 (id, ref) VALUES (1,3), (2,1), (3,2), (4,5), (4,4);
+INSERT INTO t1 SELECT * FROM t2;
+SELECT * FROM t1 AS a INNER JOIN t1 AS b USING (id) WHERE a.ref < b.ref;
+id	ref	ref
+4	4	5
+SELECT * FROM t1;
+id	ref
+1	3
+2	1
+3	2
+4	5
+4	4
+DELETE FROM a USING t1 AS a INNER JOIN t1 AS b USING (id) WHERE a.ref < b.ref;
+SELECT * FROM t1;
+id	ref
+1	3
+2	1
+3	2
+4	5
+DROP TABLE t1, t2;
 End of 5.0 tests

mysql-test/t/merge.test

@@ -507,4 +507,26 @@ SELECT * FROM tm1;
 CHECK TABLE tm1;
 DROP TABLE tm1, t1, t2;
 
+#
+# Bug #28837: MyISAM storage engine error (134) doing delete with self-join
+#
+
+CREATE TABLE t1 (id INT NOT NULL, ref INT NOT NULL, INDEX (id)) ENGINE=MyISAM;
+CREATE TABLE t2 LIKE t1;
+
+INSERT INTO t2 (id, ref) VALUES (1,3), (2,1), (3,2), (4,5), (4,4);
+INSERT INTO t1 SELECT * FROM t2;
+INSERT INTO t1 SELECT * FROM t2;
+
+CREATE TABLE t3 (id INT NOT NULL, ref INT NOT NULL, INDEX (id)) ENGINE=MERGE
+                                                                UNION(t1);
+
+SELECT * FROM t3 AS a INNER JOIN t3 AS b USING (id) WHERE a.ref < b.ref;
+SELECT * FROM t3;
+DELETE FROM a USING t3 AS a INNER JOIN t3 AS b USING (id) WHERE a.ref < b.ref;
+SELECT * FROM t3;
+
+DROP TABLE t1, t2, t3;
+
+
 --echo End of 5.0 tests

mysql-test/t/myisam.test

@@ -1161,4 +1161,21 @@ ALTER TABLE t1 ENABLE KEYS;
 SELECT a FROM t1 FORCE INDEX (inx) WHERE a=1;
 DROP TABLE t1;
 
+#
+# Bug#28837: MyISAM storage engine error (134) doing delete with self-join
+#
+
+CREATE TABLE t1 (id int NOT NULL, ref int NOT NULL, INDEX (id)) ENGINE=MyISAM;
+CREATE TABLE t2 LIKE t1;
+
+INSERT INTO t2 (id, ref) VALUES (1,3), (2,1), (3,2), (4,5), (4,4);
+INSERT INTO t1 SELECT * FROM t2;
+
+SELECT * FROM t1 AS a INNER JOIN t1 AS b USING (id) WHERE a.ref < b.ref;
+SELECT * FROM t1;
+DELETE FROM a USING t1 AS a INNER JOIN t1 AS b USING (id) WHERE a.ref < b.ref;
+SELECT * FROM t1;
+
+DROP TABLE t1, t2;
+
 --echo End of 5.0 tests

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;
 }

sql/ha_myisammrg.cc

@@ -294,9 +294,13 @@ int ha_myisammrg::index_next_same(byte * buf,
                                   const byte *key __attribute__((unused)),
                                   uint length __attribute__((unused)))
 {
+  int error;
   statistic_increment(table->in_use->status_var.ha_read_next_count,
-		      &LOCK_status);
-  int error=myrg_rnext_same(file,buf);
+                      &LOCK_status);
+  do
+  {
+    error= myrg_rnext_same(file,buf);
+  } while (error == HA_ERR_RECORD_DELETED);
   table->status=error ? STATUS_NOT_FOUND: 0;
   return error;
 }