bzr commit into mysql-5.1 branch (mhansson:2690) Bug#38499

[Martin Hansson]

#At file:///data0/martin/bzr/5.1-5.1.29-rc-fix-bug38499/

 2690 Martin Hansson	2008-09-20
      Bug#38499: flush tables and multitable table update with 
      derived table cause crash
      
      When a multi-UPDATE command fails to lock some table, and
      subsequently succeeds, the tables need to be reopened if
      they were altered. But the reopening procedure failed for
      derived tables.
      Fixed by resetting the 'prepared' flag on derived tables
      during the mentioned procedure, which causes them to be 
      reopened.
modified:
  mysql-test/r/lock_multi.result
  mysql-test/t/lock_multi.test
  sql/sql_update.cc
  sql/table.cc
  sql/table.h

per-file messages:
  mysql-test/r/lock_multi.result
    Bug#38499: Test result
  mysql-test/t/lock_multi.test
    Bug#38499: Test case
  sql/sql_update.cc
    Bug#38499: The fix.
  sql/table.cc
    Bug#38499: Definition of helper method for the fix.
  sql/table.h
    Bug#38499: Declaration of helper method for the fix.
=== modified file 'mysql-test/r/lock_multi.result'
--- a/mysql-test/r/lock_multi.result	2008-02-06 11:40:59 +0000
+++ b/mysql-test/r/lock_multi.result	2008-09-20 09:23:48 +0000
@@ -153,4 +153,10 @@ drop table t1;
 select @tlwa < @tlwb;
 @tlwa < @tlwb
 1
+CREATE TABLE t1( a INT );
+INSERT INTO t1 VALUES (1), (2), (3), (4);
+LOCK TABLES t1 WRITE;
+UPDATE t1, (SELECT 1 FROM t1 t1i) d SET a = 0 WHERE 1=0;
+ALTER TABLE t1 ADD b INT;
+UNLOCK TABLES;
 End of 5.1 tests

=== modified file 'mysql-test/t/lock_multi.test'
--- a/mysql-test/t/lock_multi.test	2008-02-22 12:35:08 +0000
+++ b/mysql-test/t/lock_multi.test	2008-09-20 09:23:48 +0000
@@ -472,4 +472,35 @@ eval SET @tlwb= SUBSTRING_INDEX('$tlwb',
 --enable_query_log
 select @tlwa < @tlwb;
 
+#
+# Bug#38499: flush tables and multitable table update with derived table cause 
+# crash
+#
+CREATE TABLE t1( a INT );
+INSERT INTO t1 VALUES (1), (2), (3), (4);
+--connect (conn1, localhost, root,,)
+LOCK TABLES t1 WRITE;
+--connect (conn2, localhost, root,,)
+--send 
+UPDATE t1, (SELECT 1 FROM t1 t1i) d SET a = 0 WHERE 1=0;
+
+--connection conn1
+
+let $wait_condition=
+  SELECT * 
+  FROM information_schema.processlist  
+  WHERE STATE = "Locked" AND 
+      info = "UPDATE t1, (SELECT 1 FROM t1 t1i) d SET a = 0 WHERE 1=0";
+--source include/wait_condition.inc
+
+ALTER TABLE t1 ADD b INT;
+UNLOCK TABLES;
+
+--disconnect conn1
+--connection conn2
+# When the bug is present, we get a server crash during this command.
+--reap
+--disconnect conn2
+--connection default
+
 --echo End of 5.1 tests

=== modified file 'sql/sql_update.cc'
--- a/sql/sql_update.cc	2008-08-26 10:01:49 +0000
+++ b/sql/sql_update.cc	2008-09-20 09:23:48 +0000
@@ -1094,7 +1094,10 @@ reopen_tables:
 
     /* We have to cleanup translation tables of views. */
     for (TABLE_LIST *tbl= table_list; tbl; tbl= tbl->next_global)
+    {
+      tbl->cleanup_select_lex();
       tbl->cleanup_items();
+    }
 
     close_tables_for_reopen(thd, &table_list);
     goto reopen_tables;

=== modified file 'sql/table.cc'
--- a/sql/table.cc	2008-09-03 14:45:40 +0000
+++ b/sql/table.cc	2008-09-20 09:23:48 +0000
@@ -3124,6 +3124,21 @@ bool TABLE_LIST::setup_underlying(THD *t
   DBUG_RETURN(FALSE);
 }
 
+/**
+   @brief Clean up AST structure (st_select_lex_unit) in order to cause a
+   table to be reopened.
+
+   @details For derived tables, you normally do not want to reopen the tables.
+   This is needed, however, if the table definition has changed. This method
+   marks the AST structure so that a reopen will take place when calling
+   st_select_lex_unit::prepare()
+ */
+void TABLE_LIST::cleanup_select_lex()
+{
+  if (derived)
+    derived->prepared= FALSE;
+}
+
 
 /*
   Prepare where expression of view

=== modified file 'sql/table.h'
--- a/sql/table.h	2008-09-03 14:45:40 +0000
+++ b/sql/table.h	2008-09-20 09:23:48 +0000
@@ -1357,6 +1357,7 @@ struct TABLE_LIST
   int view_check_option(THD *thd, bool ignore_failure);
   bool setup_underlying(THD *thd);
   void cleanup_items();
+  void cleanup_select_lex();
   bool placeholder()
   {
     return derived || view || schema_table || create && !table->db_stat ||