bzr push into mysql-trunk-bugfixing branch (oystein.grovlen:3009 to 3010) Bug#51980

[Oystein.Grovlen]

 3010 oystein.grovlen@stripped	2010-04-13
      Bug#51980 mysqld service crashes with a simple COUNT(DISTINCT) query over a view
      
      Problem: Segmentation fault in add_group_and_distinct_keys() when accessing
      field of what is assumed to be an Item_field object.
      
      Cause: In case of views, the item added to list by is_indexed_agg_distinct() 
      was not of type Item_field, but Item_ref.
      
      Resolution:  Add the real Item_field object, the one referred to by 
      Item_ref object, to the list, instead.
     @ mysql-test/r/count_distinct.result
        Results for test case for Bug#51980.
     @ mysql-test/t/count_distinct.test
        Test case for Bug#51980.
        Table needs to contain at least two rows to avoid const table optimization.
     @ sql/sql_select.cc
        Make sure it is the actual Item_field object that is pushed to the out_args
        list of is_indexed_agg_distinct(), and not Item_ref objects.

    modified:
      mysql-test/r/count_distinct.result
      mysql-test/t/count_distinct.test
      sql/sql_select.cc
 3009 Alexander Nozdrin	2010-04-12 [merge]
      Auto-merge from mysql-trunk.

    removed:
      sql/lex_hash.h
      sql/sql_yacc.h
    modified:
      sql/events.h
      sql/lock.h
      sql/mysqld.h
      sql/rpl_filter.h
      sql/sp.h
      sql/sql_base.h
      sql/sql_cache.h
      sql/sql_delete.h
      sql/sql_derived.h
      sql/sql_handler.h
      sql/sql_parse.h
      sql/sql_profile.h
      sql/sql_table.h
      sql/sql_update.h
      sql/table.h
      storage/perfschema/unittest/pfs_timer-t.cc
=== modified file 'mysql-test/r/count_distinct.result'
--- a/mysql-test/r/count_distinct.result	2009-12-22 09:52:23 +0000
+++ b/mysql-test/r/count_distinct.result	2010-04-13 09:38:28 +0000
@@ -86,3 +86,11 @@ select count(distinct if(f1,3,f2)) from 
 count(distinct if(f1,3,f2))
 2
 drop table t1;
+create table t1 (i int);
+insert into t1 values (0), (1);
+create view v1 as select * from t1;
+select count(distinct i) from v1;
+count(distinct i)
+2
+drop table t1;
+drop view v1;

=== modified file 'mysql-test/t/count_distinct.test'
--- a/mysql-test/t/count_distinct.test	2009-12-22 09:52:23 +0000
+++ b/mysql-test/t/count_distinct.test	2010-04-13 09:38:28 +0000
@@ -96,3 +96,14 @@ insert into t1 values (0,1),(1,2);
 select count(distinct if(f1,3,f2)) from t1;
 drop table t1;
 
+#
+# Bug #51980 "mysqld service crashes with a simple COUNT(DISTINCT) query 
+#             over a view"
+#
+
+create table t1 (i int);
+insert into t1 values (0), (1);
+create view v1 as select * from t1;
+select count(distinct i) from v1;
+drop table t1;
+drop view v1;

=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2010-03-31 14:05:33 +0000
+++ b/sql/sql_select.cc	2010-04-13 09:38:28 +0000
@@ -4157,7 +4157,7 @@ is_indexed_agg_distinct(JOIN *join, List
         optimization is applicable 
       */
       if (out_args)
-        out_args->push_back((Item_field *) expr);
+        out_args->push_back((Item_field *) expr->real_item());
       result= true;
     }
   }


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