Backport of:

------------------------------------------------------------
revno: 2630.4.33
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w2
timestamp: Fri 2008-06-20 17:11:20 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After-review fixes in progress.

  Minimized dependency of mdl.cc on other modules (particularly
  made it independant of mysql_priv.h) in order to be able
  write unit tests for metadata locking subsystem.

sql/ha_ndbcluster_binlog.cc

@@ -141,7 +141,7 @@ static Uint64 *p_latest_trans_gci= 0;
 static TABLE *ndb_binlog_index= 0;
 static TABLE_LIST binlog_tables;
 static MDL_LOCK_DATA binlog_mdl_lock_data;
-static char binlog_mdlkey[MAX_DBKEY_LENGTH];
+static char binlog_mdlkey[MAX_MDLKEY_LENGTH];
 
 /*
   Helper functions

sql/log_event.cc

@@ -8074,7 +8074,7 @@ int Table_map_log_event::do_apply_event(Relay_log_info const *rli)
                                 &db_mem, (uint) NAME_LEN + 1,
                                 &tname_mem, (uint) NAME_LEN + 1,
                                 &mdl_lock_data, sizeof(MDL_LOCK_DATA),
-                                &mdlkey, MAX_DBKEY_LENGTH,
+                                &mdlkey, MAX_MDLKEY_LENGTH,
                                 NullS)))
     DBUG_RETURN(HA_ERR_OUT_OF_MEM);
 

sql/mdl.h

@@ -19,6 +19,7 @@
 #include "sql_plist.h"
 #include <my_sys.h>
 #include <m_string.h>
+#include <mysql_com.h>
 
 class THD;
 
@@ -148,6 +149,9 @@ void mdl_context_backup_and_reset(MDL_CONTEXT *ctx, MDL_CONTEXT *backup);
 void mdl_context_restore(MDL_CONTEXT *ctx, MDL_CONTEXT *backup);
 void mdl_context_merge(MDL_CONTEXT *target, MDL_CONTEXT *source);
 
+/** Maximal length of key for metadata locking subsystem. */
+#define MAX_MDLKEY_LENGTH (4 + NAME_LEN + 1 + NAME_LEN + 1)
+
 void mdl_init_lock(MDL_LOCK_DATA *lock_data, char *key, int type,
                    const char *db, const char *name);
 MDL_LOCK_DATA *mdl_alloc_lock(int type, const char *db, const char *name,
@@ -237,4 +241,19 @@ void* mdl_get_cached_object(MDL_LOCK_DATA *lock_data);
 void mdl_set_cached_object(MDL_LOCK_DATA *lock_data, void *cached_object,
                            mdl_cached_object_release_hook release_hook);
 
+
+/*
+  Functions in the server's kernel used by metadata locking subsystem.
+*/
+
+extern bool mysql_notify_thread_having_shared_lock(THD *thd, THD *in_use);
+extern void mysql_ha_flush(THD *thd);
+extern "C" const char *set_thd_proc_info(THD *thd, const char *info,
+                                         const char *calling_function,
+                                         const char *calling_file,
+                                         const unsigned int calling_line);
+#ifndef DBUG_OFF
+extern pthread_mutex_t LOCK_open;
+#endif
+
 #endif

sql/mysql_priv.h

@@ -1534,8 +1534,6 @@ char *generate_partition_syntax(partition_info *part_info,
                                 Alter_info *alter_info);
 #endif
 
-bool notify_thread_having_shared_lock(THD *thd, THD *in_use);
-
 enum enum_tdc_remove_table_type {TDC_RT_REMOVE_ALL, TDC_RT_REMOVE_NOT_OWN,
                                  TDC_RT_REMOVE_UNUSED};
 void tdc_remove_table(THD *thd, enum_tdc_remove_table_type remove_type,

sql/sql_base.cc

@@ -1275,7 +1275,7 @@ close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
   /*
     We need to hold LOCK_open while changing the open_tables
     list, since another thread may work on it.
-    @sa notify_thread_having_shared_lock()
+    @sa mysql_notify_thread_having_shared_lock()
   */
   pthread_mutex_lock(&LOCK_open);
 
@@ -1455,7 +1455,7 @@ void close_thread_tables(THD *thd,
   /*
     Note that we need to hold LOCK_open while changing the
     open_tables list. Another thread may work on it.
-    (See: notify_thread_having_shared_lock())
+    (See: mysql_notify_thread_having_shared_lock())
     Closing a MERGE child before the parent would be fatal if the
     other thread tries to abort the MERGE lock in between.
   */
@@ -7956,7 +7956,7 @@ void flush_tables()
          rest of the server is broken.
 */
 
-bool notify_thread_having_shared_lock(THD *thd, THD *in_use)
+bool mysql_notify_thread_having_shared_lock(THD *thd, THD *in_use)
 {
   bool signalled= FALSE;
   if ((in_use->system_thread & SYSTEM_THREAD_DELAYED_INSERT) &&
@@ -8501,7 +8501,7 @@ void close_performance_schema_table(THD *thd, Open_tables_state *backup)
   /*
     Note that we need to hold LOCK_open while changing the
     open_tables list. Another thread may work on it.
-    (See: notify_thread_having_shared_lock())
+    (See: mysql_notify_thread_having_shared_lock())
     Closing a MERGE child before the parent would be fatal if the
     other thread tries to abort the MERGE lock in between.
   */

sql/sql_handler.cc

@@ -247,7 +247,7 @@ bool mysql_ha_open(THD *thd, TABLE_LIST *tables, bool reopen)
                           &name, (uint) namelen,
                           &alias, (uint) aliaslen,
                           &mdl_lock_data, sizeof(MDL_LOCK_DATA),
-                          &mdlkey, MAX_DBKEY_LENGTH,
+                          &mdlkey, MAX_MDLKEY_LENGTH,
                           NullS)))
     {
       DBUG_PRINT("exit",("ERROR"));

sql/sql_show.cc

@@ -3084,7 +3084,7 @@ uint get_table_open_method(TABLE_LIST *tables,
    @param mdlkey         Pointer to the buffer for key for the lock request
                          (should be at least strlen(db) + strlen(name) + 2
                          bytes, or, if the lengths are not known,
-                         MAX_DBNAME_LENGTH)
+                         MAX_MDLKEY_LENGTH)
    @param table          Table list element for the table
 
    @note This is an auxiliary function to be used in cases when we want to
@@ -3157,7 +3157,7 @@ static int fill_schema_table_from_frm(THD *thd,TABLE *table,
   uint key_length;
   char db_name_buff[NAME_LEN + 1], table_name_buff[NAME_LEN + 1];
   MDL_LOCK_DATA mdl_lock_data;
-  char mdlkey[MAX_DBKEY_LENGTH];
+  char mdlkey[MAX_MDLKEY_LENGTH];
 
   bzero((char*) &table_list, sizeof(TABLE_LIST));
   bzero((char*) &tbl, sizeof(TABLE));