Backport of:

------------------------------------------------------------
revno: 2617.68.24
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-next-bg-pre2-2
timestamp: Wed 2009-09-16 17:25:29 +0400
message:
  Pre-requisite patch for fixing bug #30977 "Concurrent statement
  using stored function and DROP FUNCTION breaks SBR".

  Added MDL_request for stored routine as member to Sroutine_hash_entry
  in order to be able perform metadata locking for stored routines in
  future (Sroutine_hash_entry is an equivalent of TABLE_LIST class for
  stored routines).
(WL#4284, follow up fixes).

sql/mdl.cc:
  Introduced version of MDL_request::init() method which initializes
  lock request using pre-built MDL key.
  MDL_key::table_name/table_name_length() getters were
  renamed to reflect the fact that MDL_key objects are
  now created not only for tables.
sql/mdl.h:
  Extended enum_mdl_namespace enum with values which correspond
  to namespaces for stored functions and triggers.
  Renamed MDL_key::table_name/table_name_length() getters
  to MDL_key::name() and name_length() correspondingly to
  reflect the fact that MDL_key objects are now created
  not only for tables.
  Added MDL_key::mdl_namespace() getter.
  Also added version of MDL_request::init() method which
  initializes lock request using pre-built MDL key.
sql/sp.cc:
  Added MDL_request for stored routine as member to Sroutine_hash_entry.
  Changed code to use MDL_key from this request as a key for LEX::sroutines
  set. Removed separate "key" member from Sroutine_hash_entry as it became
  unnecessary.
sql/sp.h:
  Added MDL_request for stored routine as member to Sroutine_hash_entry
  in order to be able perform metadata locking for stored routines in
  future (Sroutine_hash_entry is an equivalent of TABLE_LIST class for
  stored routines).
  Removed Sroutine_hash_entry::key member as now we can use MDL_key from
  this request as a key for LEX::sroutines set.
sql/sp_head.cc:
  Removed sp_name::m_sroutines_key member and set_routine_type() method.
  Since key for routine in LEX::sroutines set has no longer sp_name::m_qname
  as suffix we won't save anything by creating it at sp_name construction
  time.
  Adjusted sp_name constructor used for creating temporary objects for
  lookups in SP-cache to accept MDL_key as parameter and to avoid any
  memory allocation.
  Finally, removed sp_head::m_soutines_key member for reasons similar
  to why sp_name::m_sroutines_key was removed
sql/sp_head.h:
  Removed sp_name::m_sroutines_key member and set_routine_type() method.
  Since key for routine in LEX::sroutines set has no longer sp_name::m_qname
  as suffix we won't save anything by creating it at sp_name construction
  time.
  Adjusted sp_name constructor used for creating temporary objects for
  lookups in SP-cache to accept MDL_key as parameter and to avoid any
  memory allocation.
  Finally, removed sp_head::m_soutines_key member for reasons similar
  to why sp_name::m_sroutines_key was removed.
sql/sql_base.cc:
  Adjusted code to the fact that we now use MDL_key from
  Sroutine_hash_entry::mdl_request as a key for LEX::sroutines set.
  MDL_key::table_name/table_name_length() getters were
  renamed to reflect the fact that MDL_key objects are
  now created not only for tables.
sql/sql_trigger.cc:
  sp_add_used_routine() now takes MDL_key as parameter as now we use
  instance of this class as a key for LEX::sroutines set.

1 files changed, 13 insertions, 4 deletions

diff --git a/sql/mdl.h b/sql/mdl.h
index 03631bb9dd6..868e22d0834 100644
--- a/sql/mdl.h
+++ b/sql/mdl.h
@@ -52,9 +52,14 @@ enum enum_mdl_state { MDL_PENDING, MDL_ACQUIRED };
  
   Different types of objects exist in different namespaces
    - MDL_TABLE is for tables and views.
-   - MDL_PROCEDURE is for stored procedures, stored functions and UDFs.
+   - MDL_FUNCTION is for stored functions.
+   - MDL_PROCEDURE is for stored procedures.
+   - MDL_TRIGGER is for triggers.
+  Note that although there isn't metadata locking on triggers,
+  it's necessary to have a separate namespace for them since
+  MDL_key is also used outside of the MDL subsystem.
 */
-enum enum_mdl_namespace { MDL_TABLE=0, MDL_PROCEDURE };
+enum enum_mdl_namespace { MDL_TABLE=0, MDL_FUNCTION, MDL_PROCEDURE, MDL_TRIGGER };
 
 /** Maximal length of key for metadata locking subsystem. */
 #define MAX_MDLKEY_LENGTH (1 + NAME_LEN + 1 + NAME_LEN + 1)
@@ -78,8 +83,11 @@ public:
   const char *db_name() const { return m_ptr + 1; }
   uint db_name_length() const { return m_db_name_length; }
 
-  const char *table_name() const { return m_ptr + m_db_name_length + 2; }
-  uint table_name_length() const { return m_length - m_db_name_length - 3; }
+  const char *name() const { return m_ptr + m_db_name_length + 2; }
+  uint name_length() const { return m_length - m_db_name_length - 3; }
+
+  enum_mdl_namespace mdl_namespace() const
+  { return (enum_mdl_namespace)(m_ptr[0]); }
 
   /**
     Construct a metadata lock key from a triplet (mdl_namespace, database and name).
@@ -179,6 +187,7 @@ public:
 public:
   void init(enum_mdl_namespace namespace_arg, const char *db_arg, const char *name_arg,
             enum_mdl_type mdl_type_arg);
+  void init(const MDL_key *key_arg, enum_mdl_type mdl_type_arg);
   /** Set type of lock request. Can be only applied to pending locks. */
   inline void set_type(enum_mdl_type type_arg)
   {