bzr push into mysql-5.1-telco-7.0 branch (ole.john.aske:4253 to 4254) Bug#58553

[Ole John Aske]

 4254 Ole John Aske	2011-03-24
      Cherrypicked Fix for bug#58553 to 'mysql-5.1-telco-7.0':
      
       "Queries with pushed conditions causes 'explain extended' to crash mysqld". 
                  
      handler::pushed_cond was not always properly reset when table objects where
      recycled via the table cache.
                  
      handler::pushed_cond is now set to NULL in handler::ha_reset(). This should 
      prevent pushed conditions from (incorrectly) re-apperaring in later queries.

    modified:
      sql/handler.cc
      sql/sql_base.cc
      sql/sql_select.cc
 4253 Ole John Aske	2011-03-24
      Cherry picked fix for bug#51070 to mysql-5.1-telco-7.0.
      
      Required as this fix has already been cherrypicked to the SPJ branch,
      and we want to minimize the diff between SPJ and main telco branches.
      
      See: http://lists.mysql.com/commits/117686 for original commit message.

    modified:
      mysql-test/r/subselect4.result
      mysql-test/t/subselect4.test
      sql/item_cmpfunc.cc
      sql/item_subselect.cc
=== modified file 'sql/handler.cc'
--- a/sql/handler.cc	2011-02-04 14:49:48 +0000
+++ b/sql/handler.cc	2011-03-24 10:00:09 +0000
@@ -4917,6 +4917,7 @@ int handler::ha_reset()
   free_io_cache(table);
   /* reset the bitmaps to point to defaults */
   table->default_column_bitmaps();
+  pushed_cond= NULL;
   DBUG_RETURN(reset());
 }
 

=== modified file 'sql/sql_base.cc'
--- a/sql/sql_base.cc	2010-10-22 14:13:23 +0000
+++ b/sql/sql_base.cc	2011-03-24 10:00:09 +0000
@@ -3001,6 +3001,11 @@ TABLE *open_table(THD *thd, TABLE_LIST *
   table->insert_values= 0;
   table->fulltext_searched= 0;
   table->file->ft_handler= 0;
+  /*
+    Check that there is no reference to a condtion from an earlier query
+    (cf. Bug#58553). 
+  */
+  DBUG_ASSERT(table->file->pushed_cond == NULL);
   table->reginfo.impossible_range= 0;
   /* Catch wrong handling of the auto_increment_field_not_null. */
   DBUG_ASSERT(!table->auto_increment_field_not_null);

=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2011-03-23 13:15:16 +0000
+++ b/sql/sql_select.cc	2011-03-24 10:00:09 +0000
@@ -6561,7 +6561,6 @@ make_join_select(JOIN *join,SQL_SELECT *
           tab->select_cond=sel->cond=tmp;
           /* Push condition to storage engine if this is enabled
              and the condition is not guarded */
-          tab->table->file->pushed_cond= NULL;
 	  if (thd->variables.engine_condition_pushdown)
           {
             COND *push_cond= 

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