Merge mysql.com:/home/gluh/MySQL/Merge/5.0-opt

into  mysql.com:/home/gluh/MySQL/Merge/5.1-opt


mysql-test/r/distinct.result:
  Auto merged
mysql-test/r/join_nested.result:
  Auto merged
mysql-test/r/null_key.result:
  Auto merged
mysql-test/r/select.result:
  Auto merged
mysql-test/r/subselect.result:
  Auto merged
mysql-test/r/subselect3.result:
  Auto merged
mysql-test/r/trigger.result:
  Auto merged
mysql-test/t/select.test:
  Auto merged
mysql-test/t/subselect.test:
  Auto merged
mysql-test/t/trigger.test:
  Auto merged
sql/filesort.cc:
  Auto merged
sql/item.cc:
  Auto merged
sql/item.h:
  Auto merged
sql/item_cmpfunc.cc:
  Auto merged
sql/item_cmpfunc.h:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/item_subselect.cc:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/opt_sum.cc:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
sql/sql_show.cc:
  Auto merged
sql/sql_yacc.yy:
  Auto merged
sql/table.cc:
  Auto merged
mysql-test/r/func_time.result:
  manual merge
mysql-test/r/information_schema.result:
  manual merge
mysql-test/t/func_time.test:
  manual merge
mysql-test/t/information_schema.test:
  manual merge
sql/opt_range.cc:
  manual merge
sql/sql_delete.cc:
  manual merge
sql/sql_lex.h:
  manual merge

15 files changed, 159 insertions, 59 deletions

diff --git a/sql/filesort.cc b/sql/filesort.cc
index 46ef9c9a553..58ca4837858 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -434,7 +434,8 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
   byte *ref_pos,*next_pos,ref_buff[MAX_REFLENGTH];
   my_off_t record;
   TABLE *sort_form;
-  volatile THD::killed_state *killed= &current_thd->killed;
+  THD *thd= current_thd;
+  volatile THD::killed_state *killed= &thd->killed;
   handler *file;
   MY_BITMAP *save_read_set, *save_write_set;
   DBUG_ENTER("find_all_keys");
@@ -547,6 +548,9 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
     }
     else
       file->unlock_row();
+    /* It does not make sense to read more keys in case of a fatal error */
+    if (thd->net.report_error)
+      DBUG_RETURN(HA_POS_ERROR);
   }
   if (quick_select)
   {
diff --git a/sql/item.cc b/sql/item.cc
index 0f28572163e..b88d0e92854 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -1270,7 +1270,10 @@ void Item::split_sum_func2(THD *thd, Item **ref_pointer_array,
   if (type() == SUM_FUNC_ITEM && skip_registered && 
       ((Item_sum *) this)->ref_by)
     return;                                                 
-  if (type() != SUM_FUNC_ITEM && with_sum_func)
+  if ((type() != SUM_FUNC_ITEM && with_sum_func) ||
+      (type() == FUNC_ITEM &&
+       (((Item_func *) this)->functype() == Item_func::ISNOTNULLTEST_FUNC ||
+        ((Item_func *) this)->functype() == Item_func::TRIG_COND_FUNC)))
   {
     /* Will split complicated items and ignore simple ones */
     split_sum_func(thd, ref_pointer_array, fields);
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index e131072d9bf..58aa7de073f 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -238,6 +238,10 @@ bool Item_subselect::exec()
 {
   int res;
 
+  if (thd->net.report_error)
+  /* Do not execute subselect in case of a fatal error */
+    return 1;
+
   res= engine->exec();
 
   if (engine_changed)
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index faeef7fd5db..369ab842d65 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -1007,7 +1007,8 @@ longlong Item_func_quarter::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   TIME ltime;
-  (void) get_arg0_date(&ltime, TIME_FUZZY_DATE);
+  if (get_arg0_date(&ltime, TIME_FUZZY_DATE))
+    return 0;
   return (longlong) ((ltime.month+2)/3);
 }
 
@@ -1647,6 +1648,7 @@ String *Item_func_sec_to_time::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
   TIME ltime;
+  longlong arg_val= args[0]->val_int(); 
 
   if ((null_value=args[0]->null_value) || str->alloc(19))
   {
@@ -1654,7 +1656,7 @@ String *Item_func_sec_to_time::val_str(String *str)
     return (String*) 0;
   }
 
-  sec_to_time(args[0]->val_int(), args[0]->unsigned_flag, &ltime);
+  sec_to_time(arg_val, args[0]->unsigned_flag, &ltime);
   
   make_time((DATE_TIME_FORMAT *) 0, &ltime, str);
   return str;
@@ -1665,11 +1667,12 @@ longlong Item_func_sec_to_time::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   TIME ltime;
+  longlong arg_val= args[0]->val_int(); 
   
   if ((null_value=args[0]->null_value))
     return 0;
 
-  sec_to_time(args[0]->val_int(), args[0]->unsigned_flag, &ltime);
+  sec_to_time(arg_val, args[0]->unsigned_flag, &ltime);
 
   return (ltime.neg ? -1 : 1) *
     ((ltime.hour)*10000 + ltime.minute*100 + ltime.second);
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 742efc71e63..1515fef4387 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -1151,7 +1151,8 @@ bool push_new_name_resolution_context(THD *thd,
                                       TABLE_LIST *left_op,
                                       TABLE_LIST *right_op);
 void add_join_on(TABLE_LIST *b,Item *expr);
-void add_join_natural(TABLE_LIST *a,TABLE_LIST *b,List<String> *using_fields);
+void add_join_natural(TABLE_LIST *a,TABLE_LIST *b,List<String> *using_fields,
+                      SELECT_LEX *lex);
 bool add_proc_to_list(THD *thd, Item *item);
 TABLE *unlink_open_table(THD *thd,TABLE *list,TABLE *find);
 void update_non_unique_table_error(TABLE_LIST *update,
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 628b07631c1..1e18b2d48bd 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -219,6 +219,8 @@ public:
   }
   inline void merge_flags(SEL_ARG *arg) { maybe_flag|=arg->maybe_flag; }
   inline void maybe_smaller() { maybe_flag=1; }
+  /* Return true iff it's a single-point null interval */
+  inline bool is_null_interval() { return maybe_null && max_value[0] == 1; } 
   inline int cmp_min_to_min(SEL_ARG* arg)
   {
     return sel_cmp(field,min_value, arg->min_value, min_flag, arg->min_flag);
@@ -560,7 +562,8 @@ public:
   bool is_ror_scan;
   /* Number of ranges in the last checked tree->key */
   uint n_ranges;
-};
+  uint8 first_null_comp; /* first null component if any, 0 - otherwise */
+} PARAM;
 
 class TABLE_READ_PLAN;
   class TRP_RANGE;
@@ -7016,6 +7019,7 @@ check_quick_select(PARAM *param,uint idx,SEL_ARG *tree, bool update_tbl_stats)
   DBUG_ENTER("check_quick_select");
 
   param->is_ror_scan= FALSE;
+  param->first_null_comp= 0;
 
   if (!tree)
     DBUG_RETURN(HA_POS_ERROR);			// Can't use it
@@ -7116,6 +7120,7 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree,
   ha_rows records=0, tmp;
   uint tmp_min_flag, tmp_max_flag, keynr, min_key_length, max_key_length;
   char *tmp_min_key, *tmp_max_key;
+  uint8 save_first_null_comp= param->first_null_comp;
 
   param->max_key_part=max(param->max_key_part,key_tree->part);
   if (key_tree->left != &null_element)
@@ -7153,6 +7158,9 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree,
       param->is_ror_scan= FALSE;
   }
 
+  if (!param->first_null_comp && key_tree->is_null_interval())
+    param->first_null_comp= key_tree->part+1;
+
   if (key_tree->next_key_part &&
       key_tree->next_key_part->part == key_tree->part+1 &&
       key_tree->next_key_part->type == SEL_ARG::KEY_RANGE)
@@ -7196,7 +7204,8 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree,
       (param->table->key_info[keynr].flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
       HA_NOSAME &&
       min_key_length == max_key_length &&
-      !memcmp(param->min_key,param->max_key,min_key_length))
+      !memcmp(param->min_key,param->max_key,min_key_length) &&
+      !param->first_null_comp)
   {
     tmp=1;					// Max one record
     param->n_ranges++;
@@ -7271,6 +7280,7 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree,
       return tmp;
     records+=tmp;
   }
+  param->first_null_comp= save_first_null_comp;
   return records;
 }
 
diff --git a/sql/opt_sum.cc b/sql/opt_sum.cc
index 90a3ff66a22..5bd5ec4b42d 100644
--- a/sql/opt_sum.cc
+++ b/sql/opt_sum.cc
@@ -97,9 +97,9 @@ static ulonglong get_exact_record_count(TABLE_LIST *tables)
     GROUP BY part.
 
   RETURN VALUES
-    0 No errors
-    1 if all items were resolved
-   -1 on impossible conditions
+    0                    no errors
+    1                    if all items were resolved
+    HA_ERR_KEY_NOT_FOUND on impossible conditions
     OR an error number from my_base.h HA_ERR_... if a deadlock or a lock
        wait timeout happens, for example
 */
@@ -267,7 +267,7 @@ int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds)
           if (error)
 	  {
 	    if (error == HA_ERR_KEY_NOT_FOUND || error == HA_ERR_END_OF_FILE)
-	      return -1;		       // No rows matching WHERE
+	      return HA_ERR_KEY_NOT_FOUND;	      // No rows matching WHERE
 	    /* HA_ERR_LOCK_DEADLOCK or some other error */
  	    table->file->print_error(error, MYF(0));
             return(error);
@@ -354,7 +354,7 @@ int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds)
           if (error)
           {
 	    if (error == HA_ERR_KEY_NOT_FOUND || error == HA_ERR_END_OF_FILE)
-	      return -1;		       // No rows matching WHERE
+	      return HA_ERR_KEY_NOT_FOUND;	     // No rows matching WHERE
 	    /* HA_ERR_LOCK_DEADLOCK or some other error */
  	    table->file->print_error(error, MYF(0));
             return(error);
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index bb84e89a2ef..fd2e8445132 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -3764,7 +3764,7 @@ find_field_in_natural_join(THD *thd, TABLE_LIST *table_ref, const char *name,
 {
   List_iterator_fast<Natural_join_column>
     field_it(*(table_ref->join_columns));
-  Natural_join_column *nj_col;
+  Natural_join_column *nj_col, *curr_nj_col;
   Field *found_field;
   Query_arena *arena, backup;
   DBUG_ENTER("find_field_in_natural_join");
@@ -3776,14 +3776,21 @@ find_field_in_natural_join(THD *thd, TABLE_LIST *table_ref, const char *name,
   LINT_INIT(arena);
   LINT_INIT(found_field);
 
-  for (;;)
+  for (nj_col= NULL, curr_nj_col= field_it++; curr_nj_col; 
+       curr_nj_col= field_it++)
   {
-    if (!(nj_col= field_it++))
-      DBUG_RETURN(NULL);
-
-    if (!my_strcasecmp(system_charset_info, nj_col->name(), name))
-      break;
+    if (!my_strcasecmp(system_charset_info, curr_nj_col->name(), name))
+    {
+      if (nj_col)
+      {
+        my_error(ER_NON_UNIQ_ERROR, MYF(0), name, thd->where);
+        DBUG_RETURN(NULL);
+      }
+      nj_col= curr_nj_col;
+    }
   }
+  if (!nj_col)
+    DBUG_RETURN(NULL);
 
   if (nj_col->view_field)
   {
@@ -4684,9 +4691,16 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
   {
     bool found= FALSE;
     const char *field_name_1;
+    /* true if field_name_1 is a member of using_fields */
+    bool is_using_column_1;
     if (!(nj_col_1= it_1.get_or_create_column_ref(leaf_1)))
       goto err;
     field_name_1= nj_col_1->name();
+    is_using_column_1= using_fields && 
+      test_if_string_in_list(field_name_1, using_fields);
+    DBUG_PRINT ("info", ("field_name_1=%s.%s", 
+                         nj_col_1->table_name() ? nj_col_1->table_name() : "", 
+                         field_name_1));
 
     /*
       Find a field with the same name in table_ref_2.
@@ -4703,6 +4717,10 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
       if (!(cur_nj_col_2= it_2.get_or_create_column_ref(leaf_2)))
         goto err;
       cur_field_name_2= cur_nj_col_2->name();
+      DBUG_PRINT ("info", ("cur_field_name_2=%s.%s", 
+                           cur_nj_col_2->table_name() ? 
+                             cur_nj_col_2->table_name() : "", 
+                           cur_field_name_2));
 
       /*
         Compare the two columns and check for duplicate common fields.
@@ -4710,10 +4728,16 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
         table_ref_2 (then found == TRUE), or if a field in table_ref_2
         was already matched by some previous field in table_ref_1
         (then cur_nj_col_2->is_common == TRUE).
+        Note that it is too early to check the columns outside of the
+        USING list for ambiguity because they are not actually "referenced"
+        here. These columns must be checked only on unqualified reference 
+        by name (e.g. in SELECT list).
       */
       if (!my_strcasecmp(system_charset_info, field_name_1, cur_field_name_2))
       {
-        if (found || cur_nj_col_2->is_common)
+        DBUG_PRINT ("info", ("match c1.is_common=%d", nj_col_1->is_common));
+        if (cur_nj_col_2->is_common ||
+            (found && (!using_fields || is_using_column_1)))
         {
           my_error(ER_NON_UNIQ_ERROR, MYF(0), field_name_1, thd->where);
           goto err;
@@ -4739,9 +4763,7 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
       clause (if present), mark them as common fields, and add a new
       equi-join condition to the ON clause.
     */
-    if (nj_col_2 &&
-        (!using_fields ||
-          test_if_string_in_list(field_name_1, using_fields)))
+    if (nj_col_2 && (!using_fields ||is_using_column_1))
     {
       Item *item_1=   nj_col_1->create_item(thd);
       Item *item_2=   nj_col_2->create_item(thd);
@@ -4796,6 +4818,13 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
                   eq_cond);
 
       nj_col_1->is_common= nj_col_2->is_common= TRUE;
+      DBUG_PRINT ("info", ("%s.%s and %s.%s are common", 
+                           nj_col_1->table_name() ? 
+                             nj_col_1->table_name() : "", 
+                           nj_col_1->name(),
+                           nj_col_2->table_name() ? 
+                             nj_col_2->table_name() : "", 
+                           nj_col_2->name()));
 
       if (field_1)
       {
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index e3405d9c9d9..7daf3be1578 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -69,14 +69,14 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
     Test if the user wants to delete all rows and deletion doesn't have
     any side-effects (because of triggers), so we can use optimized
     handler::delete_all_rows() method.
-
-    If row-based replication is used, we also delete the table row by
-    row.
+    We implement fast TRUNCATE for InnoDB even if triggers are present. 
+    TRUNCATE ignores triggers.
   */
   if (!using_limit && const_cond && (!conds || conds->val_int()) &&
       !(specialflag & (SPECIAL_NO_NEW_FUNC | SPECIAL_SAFE_MODE)) &&
-      !(table->triggers && table->triggers->has_delete_triggers()) &&
-      !thd->current_stmt_binlog_row_based)
+      (thd->lex->sql_command == SQLCOM_TRUNCATE ||
+       !(table->triggers && table->triggers->has_delete_triggers()))
+     )
   {
     /* Update the table->file->stats.records number */
     table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 8632ab0f675..cc52be37036 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -620,6 +620,21 @@ public:
   /* index in the select list of the expression currently being fixed */
   int cur_pos_in_select_list;
 
+  List<udf_func>     udf_list;                  /* udf function calls stack */
+  /* 
+    This is a copy of the original JOIN USING list that comes from
+    the parser. The parser :
+      1. Sets the natural_join of the second TABLE_LIST in the join
+         and the st_select_lex::prev_join_using.
+      2. Makes a parent TABLE_LIST and sets its is_natural_join/
+       join_using_fields members.
+      3. Uses the wrapper TABLE_LIST as a table in the upper level.
+    We cannot assign directly to join_using_fields in the parser because
+    at stage (1.) the parent TABLE_LIST is not constructed yet and
+    the assignment will override the JOIN USING fields of the lower level
+    joins on the right.
+  */
+  List<String> *prev_join_using;
   void init_query();
   void init_select();
   st_select_lex_unit* master_unit();
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 701a68f31b5..6d5d7328835 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -6666,11 +6666,8 @@ TABLE_LIST *st_select_lex::nest_last_join(THD *thd)
         If this is a JOIN ... USING, move the list of joined fields to the
         table reference that describes the join.
       */
-      if (table->join_using_fields)
-      {
-        ptr->join_using_fields= table->join_using_fields;
-        table->join_using_fields= NULL;
-      }
+      if (prev_join_using)
+        ptr->join_using_fields= prev_join_using;
     }
   }
   join_list->push_front(ptr);
@@ -6926,6 +6923,7 @@ void add_join_on(TABLE_LIST *b, Item *expr)
     a			Left join argument
     b			Right join argument
     using_fields        Field names from USING clause
+    lex                 The current st_select_lex
   
   IMPLEMENTATION
     This function marks that table b should be joined with a either via
@@ -6954,10 +6952,11 @@ void add_join_on(TABLE_LIST *b, Item *expr)
     None
 */
 
-void add_join_natural(TABLE_LIST *a, TABLE_LIST *b, List<String> *using_fields)
+void add_join_natural(TABLE_LIST *a, TABLE_LIST *b, List<String> *using_fields,
+                      SELECT_LEX *lex)
 {
   b->natural_join= a;
-  b->join_using_fields= using_fields;
+  lex->prev_join_using= using_fields;
 }
 
 
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index bd2a7a87c53..4966efbd366 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -717,11 +717,20 @@ JOIN::optimize()
   {
     int res;
     /*
-      opt_sum_query() returns -1 if no rows match to the WHERE conditions,
-      or 1 if all items were resolved, or 0, or an error number HA_ERR_...
+      opt_sum_query() returns HA_ERR_KEY_NOT_FOUND if no rows match
+      to the WHERE conditions,
+      or 1 if all items were resolved,
+      or 0, or an error number HA_ERR_...
     */
     if ((res=opt_sum_query(select_lex->leaf_tables, all_fields, conds)))
     {
+      if (res == HA_ERR_KEY_NOT_FOUND)
+      {
+        DBUG_PRINT("info",("No matching min/max row"));
+	zero_result_cause= "No matching min/max row";
+	error=0;
+	DBUG_RETURN(0);
+      }
       if (res > 1)
       {
         thd->fatal_error();
@@ -729,13 +738,6 @@ JOIN::optimize()
         DBUG_PRINT("error",("Error from opt_sum_query"));
 	DBUG_RETURN(1);
       }
-      if (res < 0)
-      {
-        DBUG_PRINT("info",("No matching min/max row"));
-	zero_result_cause= "No matching min/max row";
-	error=0;
-	DBUG_RETURN(0);
-      }
       DBUG_PRINT("info",("Select tables optimized away"));
       zero_result_cause= "Select tables optimized away";
       tables_list= 0;				// All tables resolved
@@ -865,6 +867,13 @@ JOIN::optimize()
   {
     ORDER *org_order= order;
     order=remove_const(this, order,conds,1, &simple_order);
+    if (thd->net.report_error)
+    {
+      error= 1;
+      DBUG_PRINT("error",("Error from remove_const"));
+      DBUG_RETURN(1);
+    }
+
     /*
       If we are using ORDER BY NULL or ORDER BY const_expression,
       return result in any order (even if we are using a GROUP BY)
@@ -874,10 +883,11 @@ JOIN::optimize()
   }
   /*
      Check if we can optimize away GROUP BY/DISTINCT.
-     We can do that if there are no aggregate functions and the
+     We can do that if there are no aggregate functions, the
      fields in DISTINCT clause (if present) and/or columns in GROUP BY
      (if present) contain direct references to all key parts of
-     an unique index (in whatever order).
+     an unique index (in whatever order) and if the key parts of the
+     unique index cannot contain NULLs.
      Note that the unique keys for DISTINCT and GROUP BY should not
      be the same (as long as they are unique).
 
@@ -972,6 +982,12 @@ JOIN::optimize()
     group_list= remove_const(this, (old_group_list= group_list), conds,
                              rollup.state == ROLLUP::STATE_NONE,
 			     &simple_group);
+    if (thd->net.report_error)
+    {
+      error= 1;
+      DBUG_PRINT("error",("Error from remove_const"));
+      DBUG_RETURN(1);
+    }
     if (old_group_list && !group_list)
       select_distinct= 0;
   }
@@ -988,6 +1004,12 @@ JOIN::optimize()
   {
     group_list= procedure->group= remove_const(this, procedure->group, conds,
 					       1, &simple_group);
+    if (thd->net.report_error)
+    {
+      error= 1;
+      DBUG_PRINT("error",("Error from remove_const"));
+      DBUG_RETURN(1);
+    }   
     calc_group_buffer(this, group_list);
   }
 
@@ -6578,6 +6600,8 @@ remove_const(JOIN *join,ORDER *first_order, COND *cond,
       *simple_order=0;				// Must do a temp table to sort
     else if (!(order_tables & not_const_tables))
     {
+      if (order->item[0]->with_subselect)
+        order->item[0]->val_str(&order->item[0]->str_value);
       DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
       continue;					// skip const item
     }
@@ -12107,7 +12131,7 @@ test_if_subkey(ORDER *order, TABLE *table, uint ref, uint ref_key_parts,
 
 
 /*
-  Check if GROUP BY/DISTINCT can be optimized away because the set is 
+  Check if GROUP BY/DISTINCT can be optimized away because the set is
   already known to be distinct.
   
   SYNOPSIS
@@ -12115,7 +12139,7 @@ test_if_subkey(ORDER *order, TABLE *table, uint ref, uint ref_key_parts,
     table                The table to operate on.
     find_func            function to iterate over the list and search
                          for a field
-  
+
   DESCRIPTION
     Used in removing the GROUP BY/DISTINCT of the following types of
     statements:
@@ -12126,12 +12150,13 @@ test_if_subkey(ORDER *order, TABLE *table, uint ref, uint ref_key_parts,
       then <any combination of a,b,c>,{whatever} is also distinct
 
     This function checks if all the key parts of any of the unique keys
-    of the table are referenced by a list : either the select list 
+    of the table are referenced by a list : either the select list
     through find_field_in_item_list or GROUP BY list through
     find_field_in_order_list.
-    If the above holds then we can safely remove the GROUP BY/DISTINCT,
+    If the above holds and the key parts cannot contain NULLs then we 
+    can safely remove the GROUP BY/DISTINCT,
     as no result set can be more distinct than an unique key.
-  
+ 
   RETURN VALUE
     1                    found
     0                    not found.
@@ -12154,7 +12179,8 @@ list_contains_unique_index(TABLE *table,
            key_part < key_part_end;
            key_part++)
       {
-        if (!find_func(key_part->field, data))
+        if (key_part->field->maybe_null() || 
+            !find_func(key_part->field, data))
           break;
       }
       if (key_part == key_part_end)
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index a895bf14ce0..48471fa56d2 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -4985,6 +4985,7 @@ bool get_schema_tables_result(JOIN *join)
 
       if (is_subselect) // is subselect
       {
+        table_list->table->file->extra(HA_EXTRA_NO_CACHE);
         table_list->table->file->extra(HA_EXTRA_RESET_STATE);
         table_list->table->file->delete_all_rows();
         free_io_cache(table_list->table);
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index eb8641f011f..caca310180d 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -7116,11 +7116,11 @@ join_table:
             YYERROR_UNLESS($1 && $3);
 	  }
 	  '(' using_list ')'
-          { add_join_natural($1,$3,$7); $$=$3; }
+          { add_join_natural($1,$3,$7,Select); $$=$3; }
 	| table_ref NATURAL JOIN_SYM table_factor
 	  {
             YYERROR_UNLESS($1 && ($$=$4));
-            add_join_natural($1,$4,NULL);
+            add_join_natural($1,$4,NULL,Select);
           }
 
 /* LEFT JOIN variants */
@@ -7147,11 +7147,15 @@ join_table:
             YYERROR_UNLESS($1 && $5);
 	  }
 	  USING '(' using_list ')'
-          { add_join_natural($1,$5,$9); $5->outer_join|=JOIN_TYPE_LEFT; $$=$5; }
+          { 
+            add_join_natural($1,$5,$9,Select); 
+            $5->outer_join|=JOIN_TYPE_LEFT; 
+            $$=$5; 
+          }
 	| table_ref NATURAL LEFT opt_outer JOIN_SYM table_factor
 	  {
             YYERROR_UNLESS($1 && $6);
- 	    add_join_natural($1,$6,NULL);
+ 	    add_join_natural($1,$6,NULL,Select);
 	    $6->outer_join|=JOIN_TYPE_LEFT;
 	    $$=$6;
 	  }
@@ -7185,12 +7189,12 @@ join_table:
 	    LEX *lex= Lex;
             if (!($$= lex->current_select->convert_right_join()))
               YYABORT;
-            add_join_natural($$,$5,$9);
+            add_join_natural($$,$5,$9,Select);
           }
 	| table_ref NATURAL RIGHT opt_outer JOIN_SYM table_factor
 	  {
             YYERROR_UNLESS($1 && $6);
-	    add_join_natural($6,$1,NULL);
+	    add_join_natural($6,$1,NULL,Select);
 	    LEX *lex= Lex;
             if (!($$= lex->current_select->convert_right_join()))
               YYABORT;
diff --git a/sql/table.cc b/sql/table.cc
index cf2eb1705a5..e911d39b225 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -3430,6 +3430,7 @@ Field *Natural_join_column::field()
 
 const char *Natural_join_column::table_name()
 {
+  DBUG_ASSERT(table_ref);
   return table_ref->alias;
 }