BUG#8804: wrong results for NULL IN (SELECT ...)

Evaluate "NULL IN (SELECT ...)" in a special way: Disable pushed-down 
conditions and their "consequences": 
 = Do full table scans instead of unique_[index_subquery] lookups.
 = Change appropriate "ref_or_null" accesses to full table scans in
   subquery's joins.
Also cache value of NULL IN (SELECT ...) if the SELECT is not correlated 
wrt any upper select.


mysql-test/r/subselect.result:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
   - Updated test results
sql/item.h:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
   - Added comments
sql/item_cmpfunc.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
  Made Item_in_optimizer to:
  - cache the value of "NULL IN (uncorrelated select)"
  - Turn off pushed-down predicates when evaluating "NULL IN (SELECT ...)"
sql/item_cmpfunc.h:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
  - Made Item_in_optimizer cache the value of "NULL IN (uncorrelated select)"
  - Added comments
sql/item_subselect.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - When needed, wrap the predicates we push into subquery into an 
    Item_func_trig_cond so we're able to turn them off when evaluating 
    NULL IN (SELECT ...).
  - Added code to evaluate NULL IN (SELECT ...) in a special way:
    = In [unique_]index_subquery, do full table scan to see if there 
      are any rows.
    = For other subqueries, change ref[_or_null] to ALL if the
      ref[_or_null] was created from pushed-down predicate.
sql/item_subselect.h:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added Item_subselect::is_correlated
  - Added comments
sql/records.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Make rr_sequential() non-static
sql/sql_lex.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added st_select_lex::is_correlated and Item_subselect::is_correlated.
sql/sql_lex.h:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added st_select_lex::is_correlated
sql/sql_select.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added KEY_FIELD::outer_ref to keep track of which ref accesses are 
    created from predicates that were pushed down into the subquery.
sql/sql_select.h:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added KEYUSE::outer_ref
mysql-test/r/subselect3.result:
  New BitKeeper file ``mysql-test/r/subselect3.result''
mysql-test/t/subselect3.test:
  New BitKeeper file ``mysql-test/t/subselect3.test''

1 files changed, 8 insertions, 3 deletions

diff --git a/sql/sql_select.h b/sql/sql_select.h
index 30b8f834ddf..629b44538d8 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -36,6 +36,8 @@ typedef struct keyuse_t {
     satisfied if val has NULL 'value'.
   */
   bool null_rejecting;
+  /* TRUE<=> This ref access is an outer subquery reference access */
+  bool outer_ref;
 } KEYUSE;
 
 class store_key;
@@ -455,10 +457,11 @@ class store_key :public Sql_alloc
   Field *to_field;				// Store data here
   char *null_ptr;
   char err;
- public:
+public:
+  bool null_key; /* TRUE <=> the value of the key has a null part */
   enum store_key_result { STORE_KEY_OK, STORE_KEY_FATAL, STORE_KEY_CONV };
   store_key(THD *thd, Field *field_arg, char *ptr, char *null, uint length)
-    :null_ptr(null),err(0)
+    :null_ptr(null), err(0), null_key(0)
   {
     if (field_arg->type() == FIELD_TYPE_BLOB)
     {
@@ -496,6 +499,7 @@ class store_key_field: public store_key
   enum store_key_result copy()
   {
     copy_field.do_copy(&copy_field);
+    null_key= to_field->is_null();
     return err != 0 ? STORE_KEY_FATAL : STORE_KEY_OK;
   }
   const char *name() const { return field_name; }
@@ -516,8 +520,8 @@ public:
   enum store_key_result copy()
   {
     int res= item->save_in_field(to_field, 1);
+    null_key= to_field->is_null() || item->null_value;
     return (err != 0 || res > 2 ? STORE_KEY_FATAL : (store_key_result) res); 
-	                 
   }
   const char *name() const { return "func"; }
 };
@@ -547,6 +551,7 @@ public:
           err= res;
       }
     }
+    null_key= to_field->is_null() || item->null_value;
     return (err > 2 ?  STORE_KEY_FATAL : (store_key_result) err);
   }
   const char *name() const { return "const"; }