MDEV-15035 Wrong results when calling a stored procedure

multiple times with different arguments.

If the ON expression of an outer join is an OR formula with one
of the disjunct being a constant formula then the expression
cannot be null-rejected if the constant formula is true. Otherwise
it can be null-rejected and if so the outer join can be converted
into inner join. This optimization was added in the patch for
mdev-4817. Yet the code had a defect: if the query was used in
a stored procedure with parameters and the constant item contained
some of them then the value of this constant item depended on the
values of the parameters. With some parameters it may be true,
for others not. The validity of conversion to inner join is checked
only once and it happens only for the first call of procedure.
So if the  parameters in the first call allowed the conversion it
was done and next calls used the transformed query though there
could be calls whose parameters made the conversion invalid.

Fixed by cheking whether the constant disjunct in the ON expression
originally contained an SP parameter. If so the expression is not
considered as null-rejected. For this check a new item's attribute
was intruduced: Item::with_param. It is calculated for each item
by fix fields() functions.
Also moved the call of optimize_constant_subqueries() in
JOIN::optimize after the call of simplify_joins(). The reason
for this is that after the optimization introduced by the patch
for mdev-4817 simplify_joins() can use the results of execution
of non-expensive constant subqueries and this is not valid.

1 files changed, 31 insertions, 12 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 39f497e3828..6fb650b975b 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1546,6 +1546,7 @@ bool Item_in_optimizer::fix_left(THD *thd, Item **ref)
   }
   eval_not_null_tables(NULL);
   with_sum_func= args[0]->with_sum_func;
+  with_param= args[0]->with_param || args[1]->with_param;
   with_field= args[0]->with_field;
   if ((const_item_cache= args[0]->const_item()))
   {
@@ -1587,6 +1588,7 @@ bool Item_in_optimizer::fix_fields(THD *thd, Item **ref)
   with_subselect= 1;
   with_sum_func= with_sum_func || args[1]->with_sum_func;
   with_field= with_field || args[1]->with_field;
+  with_param= args[0]->with_param || args[1]->with_param; 
   used_tables_cache|= args[1]->used_tables();
   const_item_cache&= args[1]->const_item();
   fixed= 1;
@@ -2108,6 +2110,7 @@ void Item_func_interval::fix_length_and_dec()
   used_tables_cache|= row->used_tables();
   not_null_tables_cache= row->not_null_tables();
   with_sum_func= with_sum_func || row->with_sum_func;
+  with_param= with_param || row->with_param;
   with_field= with_field || row->with_field;
   const_item_cache&= row->const_item();
 }
@@ -4335,6 +4338,7 @@ Item_cond::fix_fields(THD *thd, Item **ref)
   List_iterator<Item> li(list);
   Item *item;
   uchar buff[sizeof(char*)];			// Max local vars in function
+  bool is_and_cond= functype() == Item_func::COND_AND_FUNC;
   not_null_tables_cache= used_tables_cache= 0;
   const_item_cache= 1;
 
@@ -4396,26 +4400,33 @@ Item_cond::fix_fields(THD *thd, Item **ref)
 	(item= *li.ref())->check_cols(1))
       return TRUE; /* purecov: inspected */
     used_tables_cache|=     item->used_tables();
-    if (item->const_item())
+    if (item->const_item() && !item->with_param &&
+        !item->is_expensive() && !cond_has_datetime_is_null(item))
     {
-      if (!item->is_expensive() && !cond_has_datetime_is_null(item) && 
-          item->val_int() == 0)
+      if (item->val_int() == is_and_cond && top_level())
       {
         /* 
-          This is "... OR false_cond OR ..." 
+          a. This is "... AND true_cond AND ..."
+          In this case, true_cond  has no effect on cond_and->not_null_tables()
+          b. This is "... OR false_cond/null cond OR ..." 
           In this case, false_cond has no effect on cond_or->not_null_tables()
         */
       }
       else
       {
         /* 
-          This is  "... OR const_cond OR ..."
+          a. This is "... AND false_cond/null_cond AND ..."
+          The whole condition is FALSE/UNKNOWN.
+          b. This is  "... OR const_cond OR ..."
           In this case, cond_or->not_null_tables()=0, because the condition
           const_cond might evaluate to true (regardless of whether some tables
           were NULL-complemented).
         */
+        not_null_tables_cache= (table_map) 0;
         and_tables_cache= (table_map) 0;
       }
+      if (thd->is_error())
+        return TRUE;
     }
     else
     {
@@ -4427,6 +4438,7 @@ Item_cond::fix_fields(THD *thd, Item **ref)
     } 
   
     with_sum_func=	    with_sum_func || item->with_sum_func;
+    with_param=             with_param || item->with_param;
     with_field=             with_field || item->with_field;
     with_subselect|=        item->has_subquery();
     if (item->maybe_null)
@@ -4443,30 +4455,36 @@ bool
 Item_cond::eval_not_null_tables(uchar *opt_arg)
 {
   Item *item;
+  bool is_and_cond= functype() == Item_func::COND_AND_FUNC;
   List_iterator<Item> li(list);
   not_null_tables_cache= (table_map) 0;
   and_tables_cache= ~(table_map) 0;
   while ((item=li++))
   {
     table_map tmp_table_map;
-    if (item->const_item())
+    if (item->const_item() && !item->with_param &&
+        !item->is_expensive() && !cond_has_datetime_is_null(item))
     {
-      if (!item->is_expensive() && !cond_has_datetime_is_null(item) && 
-          item->val_int() == 0)
+      if (item->val_int() == is_and_cond && top_level())
       {
         /* 
-          This is "... OR false_cond OR ..." 
+          a. This is "... AND true_cond AND ..."
+          In this case, true_cond  has no effect on cond_and->not_null_tables()
+          b. This is "... OR false_cond/null cond OR ..." 
           In this case, false_cond has no effect on cond_or->not_null_tables()
         */
       }
       else
       {
         /* 
-          This is  "... OR const_cond OR ..."
+          a. This is "... AND false_cond/null_cond AND ..."
+          The whole condition is FALSE/UNKNOWN.
+          b. This is  "... OR const_cond OR ..."
           In this case, cond_or->not_null_tables()=0, because the condition
-          some_cond_or might be true regardless of what tables are 
-          NULL-complemented.
+          const_cond might evaluate to true (regardless of whether some tables
+          were NULL-complemented).
         */
+        not_null_tables_cache= (table_map) 0;
         and_tables_cache= (table_map) 0;
       }
     }
@@ -5118,6 +5136,7 @@ Item_func_regex::fix_fields(THD *thd, Item **ref)
        args[1]->fix_fields(thd, args + 1)) || args[1]->check_cols(1))
     return TRUE;				/* purecov: inspected */
   with_sum_func=args[0]->with_sum_func || args[1]->with_sum_func;
+  with_param=args[0]->with_param || args[1]->with_param;
   with_field= args[0]->with_field || args[1]->with_field;
   with_subselect= args[0]->has_subquery() || args[1]->has_subquery();
   max_length= 1;