MDEV-7219 SQL_CALC_FOUND_ROWS yields wrong result

revert the code in filesort that conditionally updated 'found_rows',
rely on filesort_limit_arg instead.

1 files changed, 3 insertions, 10 deletions

diff --git a/sql/filesort.cc b/sql/filesort.cc
index 509a7f8e9b3..027437fca67 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -166,8 +166,6 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   TABLE_LIST *tab= table->pos_in_table_list;
   Item_subselect *subselect= tab ? tab->containing_subselect() : 0;
 
-  *found_rows= HA_POS_ERROR;
-
   MYSQL_FILESORT_START(table->s->db.str, table->s->table_name.str);
   DEBUG_SYNC(thd, "filesort_start");
 
@@ -190,6 +188,7 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
   my_b_clear(&buffpek_pointers);
   buffpek=0;
   error= 1;
+  *found_rows= HA_POS_ERROR;
 
   param.init_for_filesort(sortlength(thd, sortorder, s_length,
                                      &multi_byte_charset),
@@ -690,8 +689,7 @@ static ha_rows find_all_keys(Sort_param *param, SQL_SELECT *select,
   ref_pos= ref_buff;
   quick_select=select && select->quick;
   record=0;
-  if (pq) // don't count unless pq is used
-    *found_rows= 0;
+  *found_rows= 0;
   flag= ((file->ha_table_flags() & HA_REC_NOT_IN_SEQ) || quick_select);
   if (flag)
     ref_pos= &file->ref[0];
@@ -814,14 +812,9 @@ static ha_rows find_all_keys(Sort_param *param, SQL_SELECT *select,
 
     if (write_record)
     {
+       ++(*found_rows);
       if (pq)
       {
-        /*
-          only count rows when pq is used - otherwise there might be
-          other filters *after* the filesort, we don't know the final row
-          count here
-        */
-        (*found_rows)++;
         pq->push(ref_pos);
         idx= pq->num_elements();
       }