bk commit into 4.1 tree (aelkin:1.2480) BUG#19136

[Andrei Elkin]

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4.1 repository of elkin. When elkin does a push these changes will
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ChangeSet
  1.2480 06/05/05 11:21:21 aelkin@stripped +3 -0
  Bug#19136: Crashing log-bin and uninitialized user variables in a derived table
  
  The reason of the bug is in that `get_var_with_binlog' performs missed
  assingment of
  the variables as side-effect. Doing that it eventually calls
  `free_underlaid_joins' to pass as an argument `thd->lex->select_lex' of the lex
  which belongs to the user query, not 
  to one which is emulated i.e SET @var1:=NULL.
  
  
  `get_var_with_binlog' is refined to supply a temporary lex to sql_set_variables's stack.

  sql/item_func.cc
    1.260 06/05/05 11:21:18 aelkin@stripped +10 -0
    BUG#19136: Crashing log-bin and uninitialized user variables
    
    The reason of the bug is in that how `get_var_with_binlog' performs missed
    assingment of the variables: `free_underlaid_joins' gets as an argument
`thd->lex->select_lex'
    which belongs to the user query, not to one which is emulated i.e SET @var1:=NULL.
    
    `get_var_with_binlog' is refined to supply a temporary lex to sql_set_variables's
stack.
    

  mysql-test/t/rpl_user_variables.test
    1.8 06/05/05 11:21:17 aelkin@stripped +6 -0
    a problematic query to be binlogged is added

  mysql-test/r/rpl_user_variables.result
    1.11 06/05/05 11:21:17 aelkin@stripped +1 -0
    results changed

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	aelkin
# Host:	dsl-hkigw8-feb0de00-199.dhcp.inet.fi
# Root:	/usr_rh9/home/elkin.rh9/MySQL/FIXES/4.1-bug19136_unass_user_var

--- 1.259/sql/item_func.cc	2006-04-12 22:02:02 +03:00
+++ 1.260/sql/item_func.cc	2006-05-05 11:21:18 +03:00
@@ -2733,14 +2733,24 @@
       sql_set_variables(), we could instead manually call check() and update();
       this would save memory and time; but calling sql_set_variables() makes
       one unique place to maintain (sql_set_variables()). 
+
+      Manipulation with lex is necessary since free_underlaid_joins
+      is going to release memory belonging to the main query.
     */
 
     List<set_var_base> tmp_var_list;
+    LEX *sav_lex= thd->lex, lex_tmp;
+    thd->lex= &lex_tmp;
+    lex_start(thd, NULL, 0);
     tmp_var_list.push_back(new set_var_user(new Item_func_set_user_var(name,
                                                                        new
Item_null())));
     /* Create the variable */
     if (sql_set_variables(thd, &tmp_var_list))
+    {
+      thd->lex= sav_lex;
       goto err;
+    }
+    thd->lex= sav_lex;
     if (!(var_entry= get_variable(&thd->user_vars, name, 0)))
       goto err;
   }

--- 1.10/mysql-test/r/rpl_user_variables.result	2004-06-23 13:36:02 +03:00
+++ 1.11/mysql-test/r/rpl_user_variables.result	2006-05-05 11:21:17 +03:00
@@ -105,5 +105,6 @@
 slave-bin.000001	1412	Query	1	1412	use `test`; insert into t1 values (@a),(@a)
 slave-bin.000001	1478	User var	2	1478	@`a`=NULL
 slave-bin.000001	1503	Query	1	1503	use `test`; insert into t1 values (@a),(@a),(@a*5)
+insert into t1 select * FROM (select @var1 union  select @var2) AS t2;
 drop table t1;
 stop slave;

--- 1.7/mysql-test/t/rpl_user_variables.test	2005-07-28 03:21:49 +03:00
+++ 1.8/mysql-test/t/rpl_user_variables.test	2006-05-05 11:21:17 +03:00
@@ -47,9 +47,15 @@
 sync_with_master;
 select * from t1;
 show binlog events from 141;
+
+#
+# BUG19136: Crashing log-bin and uninitialized user variables in a derived table
+# just to check nothing bad happens anymore
 connection master;
+insert into t1 select * FROM (select @var1 union  select @var2) AS t2;
 drop table t1;
 save_master_pos;
+
 connection slave;
 sync_with_master;
 stop slave;