bk commit into 4.1 tree (ingo:1.2372) BUG#9459

[ingo]

Below is the list of changes that have just been committed into a local
4.1 repository of mydev. When mydev does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2372 05/08/03 11:16:15 ingo@stripped +3 -0
  Bug#9459 - deadlock with flush with lock, and lock table write
  Added a check before taking a global read lock if
  the own thread has a write locked table.

  sql/sql_parse.cc
    1.456 05/08/03 11:16:11 ingo@stripped +17 -0
    Bug#9459 - deadlock with flush with lock, and lock table write
    Added a check before taking a global read lock if
    the own thread has a write locked table.

  mysql-test/t/flush.test
    1.16 05/08/03 11:16:11 ingo@stripped +9 -0
    Bug#9459 - deadlock with flush with lock, and lock table write
    The test case.

  mysql-test/r/flush.result
    1.12 05/08/03 11:16:10 ingo@stripped +5 -0
    Bug#9459 - deadlock with flush with lock, and lock table write
    The test result.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	ingo
# Host:	chilla.local
# Root:	/home/mydev/mysql-4.1-4100

--- 1.455/sql/sql_parse.cc	2005-08-02 02:12:27 +02:00
+++ 1.456/sql/sql_parse.cc	2005-08-03 11:16:11 +02:00
@@ -5028,6 +5028,23 @@
     if ((options & REFRESH_READ_LOCK) && thd)
     {
       /*
+        We must not try to aspire a global read lock if we have a write
+        locked table. This would lead to a deadlock when trying to
+        reopen (and re-lock) the table after the flush.
+      */
+      if (thd->locked_tables)
+      {
+        THR_LOCK_DATA **lock_p= thd->locked_tables->locks;
+        THR_LOCK_DATA **end_p= lock_p + thd->locked_tables->lock_count;
+
+        for (; lock_p < end_p; lock_p++)
+          if ((*lock_p)->type == TL_WRITE)
+          {
+            my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
+            return 1;
+          }
+      }
+      /*
 	Writing to the binlog could cause deadlocks, as we don't log
 	UNLOCK TABLES
       */

--- 1.11/mysql-test/r/flush.result	2003-08-07 20:17:21 +02:00
+++ 1.12/mysql-test/r/flush.result	2005-08-03 11:16:10 +02:00
@@ -27,3 +27,8 @@
 n
 345
 drop table t1;
+create table t1 (c1 int);
+lock table t1 write;
+flush tables with read lock;
+ERROR HY000: Can't execute the given command because you have active locked tables or an
active transaction
+drop table t1;

--- 1.15/mysql-test/t/flush.test	2005-07-28 02:21:41 +02:00
+++ 1.16/mysql-test/t/flush.test	2005-08-03 11:16:11 +02:00
@@ -70,4 +70,13 @@
 select * from t1;
 drop table t1;
 
+#
+# Bug#9459 - deadlock with flush with lock, and lock table write
+#
+create table t1 (c1 int);
+lock table t1 write;
+--error 1192
+flush tables with read lock;
+drop table t1;
+
 # End of 4.1 tests