Merge quadxeon.mysql.com:/benchmarks/ext3/TOSAVE/tsmith/bk/50

into  quadxeon.mysql.com:/benchmarks/ext3/TOSAVE/tsmith/bk/maint/50


configure.in:
  Auto merged
mysql-test/r/strict.result:
  Auto merged
mysql-test/r/type_datetime.result:
  Auto merged
mysql-test/t/type_datetime.test:
  Auto merged
sql/item.cc:
  Auto merged
sql/item_cmpfunc.cc:
  Auto merged

6 files changed, 112 insertions, 22 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 4f7d1cb56c0..92ea35072f9 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -3522,7 +3522,8 @@ Item_field::fix_outer_field(THD *thd, Field **from_field, Item **reference)
           prev_subselect_item->const_item_cache= 0;
           set_field(*from_field);
           if (!last_checked_context->select_lex->having_fix_field &&
-              select->group_list.elements)
+              select->group_list.elements &&
+              (place == SELECT_LIST || place == IN_HAVING))
           {
             Item_outer_ref *rf;
             /*
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 92a6f5c06da..0de9ef3e9ad 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -637,7 +637,13 @@ Arg_comparator::can_compare_as_dates(Item *a, Item *b, ulonglong *const_value)
 
   if (cmp_type != CMP_DATE_DFLT)
   {
-    if (cmp_type != CMP_DATE_WITH_DATE && str_arg->const_item())
+    /*
+      Do not cache GET_USER_VAR() function as its const_item() may return TRUE
+      for the current thread but it still may change during the execution.
+    */
+    if (cmp_type != CMP_DATE_WITH_DATE && str_arg->const_item() &&
+        (str_arg->type() != Item::FUNC_ITEM ||
+        ((Item_func*)str_arg)->functype() != Item_func::GUSERVAR_FUNC))
     {
       THD *thd= current_thd;
       ulonglong value;
@@ -665,7 +671,7 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
                                         Item_result type)
 {
   enum enum_date_cmp_type cmp_type;
-  ulonglong const_value;
+  ulonglong const_value= (ulonglong)-1;
   a= a1;
   b= a2;
 
@@ -678,8 +684,7 @@ int Arg_comparator::set_cmp_func(Item_bool_func2 *owner_arg,
     a_cache= 0;
     b_cache= 0;
 
-    if (cmp_type != CMP_DATE_WITH_DATE &&
-        ((*b)->const_item() || (*a)->const_item()))
+    if (const_value != (ulonglong)-1)
     {
       Item_cache_int *cache= new Item_cache_int();
       /* Mark the cache as non-const to prevent re-caching. */
@@ -785,7 +790,12 @@ get_datetime_value(THD *thd, Item ***item_arg, Item **cache_arg,
       MYSQL_TYPE_DATE ? MYSQL_TIMESTAMP_DATE : MYSQL_TIMESTAMP_DATETIME;
     value= get_date_from_str(thd, str, t_type, warn_item->name, &error);
   }
-  if (item->const_item() && cache_arg)
+  /*
+    Do not cache GET_USER_VAR() function as its const_item() may return TRUE
+    for the current thread but it still may change during the execution.
+  */
+  if (item->const_item() && cache_arg && (item->type() != Item::FUNC_ITEM ||
+      ((Item_func*)item)->functype() != Item_func::GUSERVAR_FUNC))
   {
     Item_cache_int *cache= new Item_cache_int();
     /* Mark the cache as non-const to prevent re-caching. */
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 4579ecd48ae..d6b31d43389 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -3339,6 +3339,10 @@ String* Item_func_group_concat::val_str(String* str)
   DBUG_ASSERT(fixed == 1);
   if (null_value)
     return 0;
+  if (!result.length() && tree)
+    /* Tree is used for sorting as in ORDER BY */
+    tree_walk(tree, (tree_walk_action)&dump_leaf_key, (void*)this,
+              left_root_right);
   if (count_cut_values && !warning)
   {
     /*
@@ -3350,11 +3354,6 @@ String* Item_func_group_concat::val_str(String* str)
                           ER_CUT_VALUE_GROUP_CONCAT,
                           ER(ER_CUT_VALUE_GROUP_CONCAT));
   }
-  if (result.length())
-    return &result;
-  if (tree)
-    tree_walk(tree, (tree_walk_action)&dump_leaf_key, (void*)this,
-              left_root_right);
   return &result;
 }
 
diff --git a/sql/opt_sum.cc b/sql/opt_sum.cc
index 9222e15ff91..b9de54dbf5c 100644
--- a/sql/opt_sum.cc
+++ b/sql/opt_sum.cc
@@ -206,12 +206,68 @@ int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds)
 
           if (!ref.key_length)
             error= table->file->index_first(table->record[0]);
-          else
-	    error= table->file->index_read(table->record[0],key_buff,
-					   ref.key_length,
-					   range_fl & NEAR_MIN ?
-					   HA_READ_AFTER_KEY :
-					   HA_READ_KEY_OR_NEXT);
+          else 
+          {
+            /*
+              Use index to replace MIN/MAX functions with their values
+              according to the following rules:
+           
+              1) Insert the minimum non-null values where the WHERE clause still
+                 matches, or
+              2) a NULL value if there are only NULL values for key_part_k.
+              3) Fail, producing a row of nulls
+
+              Implementation: Read the smallest value using the search key. If
+              the interval is open, read the next value after the search
+              key. If read fails, and we're looking for a MIN() value for a
+              nullable column, test if there is an exact match for the key.
+            */
+            if (!(range_fl & NEAR_MIN))
+              /* 
+                 Closed interval: Either The MIN argument is non-nullable, or
+                 we have a >= predicate for the MIN argument.
+              */
+              error= table->file->index_read(table->record[0], ref.key_buff,
+                                             ref.key_length, 
+                                             HA_READ_KEY_OR_NEXT);
+            else
+            {
+              /*
+                Open interval: There are two cases:
+                1) We have only MIN() and the argument column is nullable, or
+                2) there is a > predicate on it, nullability is irrelevant.
+                We need to scan the next bigger record first.
+              */
+              error= table->file->index_read(table->record[0], ref.key_buff, 
+                                             ref.key_length, HA_READ_AFTER_KEY);
+              /* 
+                 If the found record is outside the group formed by the search
+                 prefix, or there is no such record at all, check if all
+                 records in that group have NULL in the MIN argument
+                 column. If that is the case return that NULL.
+
+                 Check if case 1 from above holds. If it does, we should read
+                 the skipped tuple.
+              */
+              if (ref.key_buff[prefix_len] == 1 && 
+                  /* 
+                     Last keypart (i.e. the argument to MIN) is set to NULL by
+                     find_key_for_maxmin only if all other keyparts are bound
+                     to constants in a conjunction of equalities. Hence, we
+                     can detect this by checking only if the last keypart is
+                     NULL.
+                  */                     
+                  (error == HA_ERR_KEY_NOT_FOUND ||
+                   key_cmp_if_same(table, ref.key_buff, ref.key, prefix_len)))
+              {
+                DBUG_ASSERT(item_field->field->real_maybe_null());
+                error= table->file->index_read(table->record[0], ref.key_buff,
+                                               ref.key_length, 
+                                               HA_READ_KEY_EXACT);
+              }
+            }
+          }
+          /* Verify that the read tuple indeed matches the search key */
 	  if (!error && reckey_in_range(0, &ref, item_field->field, 
 			                conds, range_fl, prefix_len))
 	    error= HA_ERR_KEY_NOT_FOUND;
@@ -739,14 +795,24 @@ static bool find_key_for_maxmin(bool max_fl, TABLE_REF *ref,
           if (!max_fl && key_part_used == key_part_to_use && part->null_bit)
           {
             /*
-              SELECT MIN(key_part2) FROM t1 WHERE key_part1=const
-              If key_part2 may be NULL, then we want to find the first row
-              that is not null
+              The query is on this form:
+
+              SELECT MIN(key_part_k) 
+              FROM t1 
+              WHERE key_part_1 = const and ... and key_part_k-1 = const
+
+              If key_part_k is nullable, we want to find the first matching row
+              where key_part_k is not null. The key buffer is now {const, ...,
+              NULL}. This will be passed to the handler along with a flag
+              indicating open interval. If a tuple is read that does not match
+              these search criteria, an attempt will be made to read an exact
+              match for the key buffer.
             */
+            /* Set the first byte of key_part_k to 1, that means NULL */
             ref->key_buff[ref->key_length]= 1;
             ref->key_length+= part->store_length;
             *range_fl&= ~NO_MIN_RANGE;
-            *range_fl|= NEAR_MIN;                // > NULL
+            *range_fl|= NEAR_MIN; // Open interval
           }
           /*
             The following test is false when the key in the key tree is
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 967322600a7..ea59cbbe9f2 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -976,6 +976,12 @@ JOIN::optimize()
     }
   }
 
+  if (conds &&!outer_join && const_table_map != found_const_table_map && 
+      (select_options & SELECT_DESCRIBE) &&
+      select_lex->master_unit() == &thd->lex->unit) // upper level SELECT
+  {
+    conds=new Item_int((longlong) 0,1);	// Always false
+  }
   if (make_join_select(this, select, conds))
   {
     zero_result_cause=
diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 7fb75732012..373b03d45e6 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -147,8 +147,16 @@ st_select_lex_unit::init_prepare_fake_select_lex(THD *thd_arg)
   fake_select_lex->table_list.link_in_list((byte *)&result_table_list,
 					   (byte **)
 					   &result_table_list.next_local);
-  fake_select_lex->context.table_list= fake_select_lex->context.first_name_resolution_table= 
+  fake_select_lex->context.table_list= 
+    fake_select_lex->context.first_name_resolution_table= 
     fake_select_lex->get_table_list();
+  if (!fake_select_lex->first_execution)
+  {
+    for (ORDER *order= (ORDER *) global_parameters->order_list.first;
+         order;
+         order= order->next)
+      order->item= &order->item_ptr;
+  }
   for (ORDER *order= (ORDER *)global_parameters->order_list.first;
        order;
        order=order->next)