Bug #29644: alter table hangs if records locked in share mode

by long running transaction

On Windows opened files can't be deleted. There was a special
upgraded lock mode (TL_WRITE instead of TL_WRITE_ALLOW_READ) 
in ALTER TABLE to make sure nobody has the table opened
when deleting the old table in ALTER TABLE. This special mode
was causing ALTER TABLE to hang waiting on a lock inside InnoDB.
This special lock is no longer necessary as the server is 
closing the tables it needs to delete in ALTER TABLE.
Fixed by removing the special lock.
Note that this also reverses the fix for bug 17264 that deals with
another consequence of this special lock mode being used.


mysql-test/r/innodb_mysql.result:
  Bug #29644: test case
mysql-test/t/innodb_mysql.test:
  Bug #29644: test case
sql/ha_innodb.cc:
  Bug #29644: reverse the (now excessive) fix
  for bug 17264 (but leave the test case).
sql/sql_base.cc:
  Bug #29644: don't need a special lock mode for Win32 anymore: 
  the table is closed before the drop.

1 files changed, 51 insertions, 0 deletions

diff --git a/mysql-test/t/innodb_mysql.test b/mysql-test/t/innodb_mysql.test
index d4ce997ddb1..a8724d2e7d5 100644
--- a/mysql-test/t/innodb_mysql.test
+++ b/mysql-test/t/innodb_mysql.test
@@ -741,4 +741,55 @@ set @@sort_buffer_size=default;
 
 DROP TABLE t1,t2;
 
+#
+# Bug #29644: alter table hangs if records locked in share mode by long
+# running transaction
+#
+
+CREATE TABLE t1 (a INT, PRIMARY KEY (a)) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES (1),(2),(3),(4),(5),(6),(7),(8);
+INSERT INTO t1 SELECT a + 8  FROM t1;
+INSERT INTO t1 SELECT a + 16 FROM t1;
+
+DELIMITER |;
+CREATE PROCEDURE p1 ()
+BEGIN
+  DECLARE i INT DEFAULT 50;
+  DECLARE cnt INT;
+  START TRANSACTION;
+    ALTER TABLE t1 ENGINE=InnoDB;
+  COMMIT;
+  START TRANSACTION;
+  WHILE (i > 0) DO
+    SET i = i - 1;
+    SELECT COUNT(*) INTO cnt FROM t1 LOCK IN SHARE MODE;
+  END WHILE;
+  COMMIT;
+END;|
+
+DELIMITER ;|
+
+CONNECT (con1,localhost,root,,);
+CONNECT (con2,localhost,root,,);
+
+CONNECTION con1;
+SEND CALL p1();
+CONNECTION con2;
+SEND CALL p1();
+CONNECTION default;
+CALL p1();
+
+CONNECTION con1;
+REAP;
+CONNECTION con2;
+REAP;
+CONNECTION default;
+DISCONNECT con1;
+DISCONNECT con2;
+
+DROP PROCEDURE p1;
+DROP TABLE t1;
+
+
 --echo End of 5.0 tests