Backport of:

------------------------------------------------------------
revno: 2630.4.18
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w2
timestamp: Tue 2008-06-03 21:07:58 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review fixes in progress.

  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all requests
  for this object in the context. This makes API a bit more clear
  and makes adjust_mdl_locks_upgradability() much nicer.


sql/lock.cc:
  lock_table_names():
    Set TABLE_LIST::mdl_lock_data when allocating new metadata
    lock request object for table list element.
sql/mdl.cc:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context. Adjusted upgrade/
  downgrade functions accordingly.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually. To simplify this process
  mdl_release_all_locks_for_name() was introduced.
sql/mdl.h:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context. Adjusted upgrade/
  downgrade functions accordingly.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually. To simplify this process
  mdl_release_all_locks_for_name() was introduced.
sql/sql_base.cc:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually.
sql/sql_parse.cc:
  adjust_mdl_locks_upgradability() is much simplier now due to the
  fact that now during upgrading/downgrading metadata locks we
  deal with individual metadata lock requests rather than with
  all requests for this object in the context.
sql/sql_table.cc:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context. Adjusted upgrade/
  downgrade functions accordingly.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually. To simplify this process
  mdl_release_all_locks_for_name() was introduced.
sql/sql_trigger.cc:
  ow during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context.

1 files changed, 3 insertions, 2 deletions

diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index 4e2b77292d8..caf5c84e1f9 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -527,8 +527,9 @@ end:
     locks. Otherwise call to close_thread_tables() will take care about both
     TABLE instance created by reopen_name_locked_table() and meta-data lock.
   */
-  if (thd->locked_tables)
-    mdl_downgrade_exclusive_locks(&thd->mdl_context);
+  if (thd->locked_tables && tables && tables->table)
+    mdl_downgrade_exclusive_lock(&thd->mdl_context,
+                                 tables->table->mdl_lock_data);
 
   if (need_start_waiting)
     start_waiting_global_read_lock(thd);