bk commit into 5.1 tree (istruewing:1.2610) BUG#26379

[Ingo Struewing]

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

ChangeSet@stripped, 2007-09-22 11:08:21+02:00, istruewing@stripped +3 -0
  Bug#26379 - Combination of FLUSH TABLE and REPAIR TABLE corrupts a MERGE table
  
  Not to be pushed. These are fixes on top of the second patch.
  They fix problems detected during first coarse review.

  mysql-test/r/merge.result@stripped, 2007-09-22 11:08:17+02:00, istruewing@stripped +20
-0
    Bug#26379 - Combination of FLUSH TABLE and REPAIR TABLE corrupts a MERGE table
    Added test result.

  mysql-test/t/merge.test@stripped, 2007-09-22 11:08:17+02:00, istruewing@stripped +14 -0
    Bug#26379 - Combination of FLUSH TABLE and REPAIR TABLE corrupts a MERGE table
    Added tests.

  sql/sql_base.cc@stripped, 2007-09-22 11:08:17+02:00, istruewing@stripped +26 -13
    Bug#26379 - Combination of FLUSH TABLE and REPAIR TABLE corrupts a MERGE table
    Fixed explicit use of MERGE child under LOCK TABLES when they have not been
    locked explicitly.
    Fixed dropping a locked MERGE table by detaching children first.
    Removed children list from open_tables() TABLE_LIST list regardless of the
    type of failure in open_table(). The list might be reused in any case.

diff -Nrup a/mysql-test/r/merge.result b/mysql-test/r/merge.result
--- a/mysql-test/r/merge.result	2007-09-12 22:11:44 +02:00
+++ b/mysql-test/r/merge.result	2007-09-22 11:08:17 +02:00
@@ -953,6 +953,20 @@ c1
 1
 2
 DROP TABLE t4;
+CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2)
+INSERT_METHOD=FIRST SELECT * FROM t3;
+SHOW CREATE TABLE t4;
+Table	Create Table
+t4	CREATE TABLE `t4` (
+  `c1` int(11) DEFAULT NULL
+) ENGINE=MRG_MyISAM DEFAULT CHARSET=latin1 INSERT_METHOD=FIRST UNION=(`t1`,`t2`)
+SELECT * FROM t4;
+c1
+1
+2
+1
+2
+DROP TABLE t4;
 LOCK TABLES t1 WRITE, t2 WRITE, t3 READ;
 CREATE TABLE t4 (c1 INT);
 DROP TABLE t4;
@@ -961,6 +975,12 @@ ERROR HY000: Table 't4' was not locked w
 CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2)
 INSERT_METHOD=LAST SELECT * FROM t3;
 ERROR HY000: Table 't4' was not locked with LOCK TABLES
+UNLOCK TABLES;
+CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2);
+LOCK TABLES t4 READ;
+SELECT * from t1, t4;
+ERROR HY000: Table 't1' was not locked with LOCK TABLES
+DROP TABLE t4;
 UNLOCK TABLES;
 DROP TABLE t1, t2, t3;
 CREATE TABLE t1 (c1 INT) ENGINE= MyISAM;
diff -Nrup a/mysql-test/t/merge.test b/mysql-test/t/merge.test
--- a/mysql-test/t/merge.test	2007-09-12 22:11:44 +02:00
+++ b/mysql-test/t/merge.test	2007-09-22 11:08:17 +02:00
@@ -676,11 +676,18 @@ CREATE TABLE t1 (c1 INT);
 CREATE TABLE t2 (c1 INT);
 CREATE TABLE t3 (c1 INT);
 INSERT INTO t3 VALUES (1), (2);
+# Show that LAST table is opened.
 CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2)
   INSERT_METHOD=LAST SELECT * FROM t3;
 SHOW CREATE TABLE t4;
 SELECT * FROM t4;
 DROP TABLE t4;
+# Show that FIRST table is opened.
+CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2)
+  INSERT_METHOD=FIRST SELECT * FROM t3;
+SHOW CREATE TABLE t4;
+SELECT * FROM t4;
+DROP TABLE t4;
 LOCK TABLES t1 WRITE, t2 WRITE, t3 READ;
 CREATE TABLE t4 (c1 INT);
 DROP TABLE t4;
@@ -689,6 +696,13 @@ CREATE TABLE t4 (c1 INT) SELECT * FROM t
 --error ER_TABLE_NOT_LOCKED
 CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2)
   INSERT_METHOD=LAST SELECT * FROM t3;
+UNLOCK TABLES;
+CREATE TABLE t4 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1,t2);
+LOCK TABLES t4 READ;
+--error ER_TABLE_NOT_LOCKED
+SELECT * from t1, t4;
+# Show that dropping a lcked MERGE table works.
+DROP TABLE t4;
 UNLOCK TABLES;
 DROP TABLE t1, t2, t3;
 
diff -Nrup a/sql/sql_base.cc b/sql/sql_base.cc
--- a/sql/sql_base.cc	2007-09-12 22:11:44 +02:00
+++ b/sql/sql_base.cc	2007-09-22 11:08:17 +02:00
@@ -1850,6 +1850,7 @@ void close_temporary(TABLE *table, bool 
   DBUG_PRINT("tmptable", ("closing table: '%s'.'%s'",
                           table->s->db.str, table->s->table_name.str));
 
+  /* Detach MERGE children, but do not clear references. It's deleted anyway. */
   if (table->child_l)
     detach_merge_children(table, FALSE);
   free_io_cache(table);
@@ -2437,9 +2438,14 @@ TABLE *open_table(THD *thd, TABLE_LIST *
                    table->s->table_name.str);
           DBUG_RETURN(0);
         }
+        /*
+          When looking for a usable TABLE, ignore MERGE children, as they
+          belong to their parent and cannot be used explicitly.
+        */
         if (!my_strcasecmp(system_charset_info, table->alias, alias) &&
             table->query_id != thd->query_id && /* skip tables already used
*/
-            !(thd->prelocked_mode && table->query_id))
+            !(thd->prelocked_mode && table->query_id) &&
+            !table->parent)
         {
           int distance= ((int) table->reginfo.lock_type -
                          (int) table_list->lock_type);
@@ -3419,6 +3425,12 @@ TABLE *drop_locked_tables(THD *thd,const
         if (table->db_stat)
         {
           table->db_stat= 0;
+          /*
+            When closing a MERGE parent table, detach its children first.
+            Clear child table references in case this object is opened again.
+          */
+          if (table->child_l)
+            detach_merge_children(table, TRUE);
           table->file->close();
         }
       }
@@ -4009,6 +4021,19 @@ int open_tables(THD *thd, TABLE_LIST **s
 	goto process_view_routines;
       }
 
+      /*
+        If in a MERGE table open, we need to remove the children list
+        from statement table list before restarting. Otherwise the list
+        will be inserted another time.
+      */
+      if (tables->parent_l)
+      {
+        TABLE_LIST *parent_l= tables->parent_l;
+        /* The parent table should be correctly open at this point. */
+        DBUG_ASSERT(parent_l->table);
+        parent_l->next_global= *parent_l->table->child_last_l;
+      }
+
       if (refresh)				// Refresh in progress
       {
         /*
@@ -4027,18 +4052,6 @@ int open_tables(THD *thd, TABLE_LIST **s
         */
         if (query_tables_last_own)
           thd->lex->mark_as_requiring_prelocking(query_tables_last_own);
-        /*
-          If in a MERGE table open, we need to remove the children list
-          from statement table list before restarting. Otherwise the list
-          will be inserted another time.
-        */
-        if (tables->parent_l)
-        {
-          TABLE_LIST *parent_l= tables->parent_l;
-          /* The parent table should be correctly open at this point. */
-          DBUG_ASSERT(parent_l->table);
-          parent_l->next_global= *parent_l->table->child_last_l;
-        }
         close_tables_for_reopen(thd, start);
 	goto restart;
       }