bzr commit into mysql-5.1-bugteam branch (v.narayanan:3197) Bug#47762

[V Narayanan]

#At file:///home/narayanan/Work/mysql_checkouts/shared_repository_directory/mysql-5.1-bugteam-47762/ based on revid:joro@stripped

 3197 V Narayanan	2009-10-30
      Bug#47762 Incorrect result from MIN() when WHERE tests NOT NULL column for NULL
      
      The lookup of a NULL value in a column having a NOT NULL
      index was resulting in wrong query result. This was happening
      due to the return value, from the function that stored the
      field value, being ignored.
     @ sql/opt_sum.cc
        Bug#47762 Incorrect result from MIN() when WHERE tests NOT NULL column for NULL
        
        Ensure that the error (or not) from the store_val_in_field
        function is used while determining the usability of the index
        (determined by the return value of the matching_cond function).
     @ sql/sql_select.cc
        Bug#47762 Incorrect result from MIN() when WHERE tests NOT NULL column for NULL
        
        Ensure that all the three cases of no error, conversion
        and error are reported by the store_val_in_field function.
     @ sql/sql_select.h
        Bug#47762 Incorrect result from MIN() when WHERE tests NOT NULL column for NULL
        
        The store_val_in_field function returns a int instead of
        a bool so that it can handle all the three cases, namely,
        error, conversion and no error.

    modified:
      sql/opt_sum.cc
      sql/sql_select.cc
      sql/sql_select.h
=== modified file 'sql/opt_sum.cc'
--- a/sql/opt_sum.cc	2009-10-14 08:46:50 +0000
+++ b/sql/opt_sum.cc	2009-10-30 12:24:33 +0000
@@ -599,6 +599,12 @@ static bool matching_cond(bool max_fl, T
                           key_part_map *key_part_used, uint *range_fl,
                           uint *prefix_len)
 {
+  /*
+    contains the error that may occur when trying to store a
+    field value
+  */
+  int store_value_in_field_error;
+
   if (!cond)
     return 1;
   Field *field= field_part->field;
@@ -723,8 +729,10 @@ static bool matching_cond(bool max_fl, T
     }
     else
     {
-      store_val_in_field(part->field, args[between && max_fl ? 2 : 1],
-                         CHECK_FIELD_IGNORE);
+      store_value_in_field_error=
+                         store_val_in_field(part->field,
+                                            args[between && max_fl ? 2 : 1],
+                                            CHECK_FIELD_IGNORE);
       if (part->null_bit) 
         *key_ptr++= (uchar) test(part->field->is_null());
       part->field->get_key_image(key_ptr, part->length, Field::itRAW);
@@ -751,6 +759,14 @@ static bool matching_cond(bool max_fl, T
   }
   else if (is_field_part)
     *range_fl&= ~(max_fl ? NO_MIN_RANGE : NO_MAX_RANGE);
+  
+  /*
+    If an error has occurred when trying to store the value
+    return 0 to indicate failure
+  */
+  if (store_value_in_field_error == -1)
+    return 0;
+
   return 1;  
 }
 

=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc	2009-10-22 09:40:15 +0000
+++ b/sql/sql_select.cc	2009-10-30 12:24:33 +0000
@@ -5735,13 +5735,15 @@ get_store_key(THD *thd, KEYUSE *keyuse, 
   This function is only called for const items on fields which are keys.
 
   @return
-    returns 1 if there was some conversion made when the field was stored.
+    returns  0 to signify no error or conversion
+    returns  1 if there was some conversion made when the field was stored.
+    returns -1 to signify error
 */
 
-bool
+int
 store_val_in_field(Field *field, Item *item, enum_check_fields check_flag)
 {
-  bool error;
+  int error;
   TABLE *table= field->table;
   THD *thd= table->in_use;
   ha_rows cuted_fields=thd->cuted_fields;
@@ -5758,7 +5760,19 @@ store_val_in_field(Field *field, Item *i
   error= item->save_in_field(field, 1);
   thd->count_cuted_fields= old_count_cuted_fields;
   dbug_tmp_restore_column_map(table->write_set, old_map);
-  return error || cuted_fields != thd->cuted_fields;
+
+  /*
+    In the value being returned we handle three cases
+    1)  0 meaning no error or truncation has occurred
+    2)  1 meaning there has been a truncation
+    3) -1 meaning there is an error when trying to store the value
+  */
+  if (error)
+    return error;
+  else if (cuted_fields != thd->cuted_fields)
+    return 1;
+  
+  return 0;
 }
 
 

=== modified file 'sql/sql_select.h'
--- a/sql/sql_select.h	2009-10-14 08:46:50 +0000
+++ b/sql/sql_select.h	2009-10-30 12:24:33 +0000
@@ -558,7 +558,7 @@ extern const char *join_type_str[];
 void TEST_join(JOIN *join);
 
 /* Extern functions in sql_select.cc */
-bool store_val_in_field(Field *field, Item *val, enum_check_fields check_flag);
+int store_val_in_field(Field *field, Item *val, enum_check_fields check_flag);
 TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 			ORDER *group, bool distinct, bool save_sum_fields,
 			ulonglong select_options, ha_rows rows_limit,


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