BUG#49902 - SELECT returns incorrect results

Queries optimized with GROUP_MIN_MAX didn't cleanup KEYREAD
optimization properly. As a result subsequent queries may
return incomplete rows (fields are initialized to default
values).

mysql-test/r/group_min_max.result:
  A test case for BUG#49902.
mysql-test/t/group_min_max.test:
  A test case for BUG#49902.
sql/opt_range.cc:
  Refactor of KEYREAD optimization switch so that KEYREAD
  handler state is in sync with st_table::key_read flag.
  
  All SQL code is supposed to switch KEYREAD optimization
  via st_table::set_keyread().
sql/opt_sum.cc:
  Refactor of KEYREAD optimization switch so that KEYREAD
  handler state is in sync with st_table::key_read flag.
  
  All SQL code is supposed to switch KEYREAD optimization
  via st_table::set_keyread().
sql/sql_select.cc:
  Refactor of KEYREAD optimization switch so that KEYREAD
  handler state is in sync with st_table::key_read flag.
  
  All SQL code is supposed to switch KEYREAD optimization
  via st_table::set_keyread().
sql/sql_update.cc:
  Refactor of KEYREAD optimization switch so that KEYREAD
  handler state is in sync with st_table::key_read flag.
  
  All SQL code is supposed to switch KEYREAD optimization
  via st_table::set_keyread().
sql/table.cc:
  Refactor of KEYREAD optimization switch so that KEYREAD
  handler state is in sync with st_table::key_read flag.
  
  All SQL code is supposed to switch KEYREAD optimization
  via st_table::set_keyread().
sql/table.h:
  Refactor of KEYREAD optimization switch so that KEYREAD
  handler state is in sync with st_table::key_read flag.
  
  All SQL code is supposed to switch KEYREAD optimization
  via st_table::set_keyread().

1 files changed, 1 insertions, 8 deletions

diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 433e2619aca..32add8679ef 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -397,10 +397,7 @@ int mysql_update(THD *thd,
       matching rows before updating the table!
     */
     if (used_index < MAX_KEY && old_covering_keys.is_set(used_index))
-    {
-      table->key_read=1;
       table->mark_columns_used_by_index(used_index);
-    }
     else
     {
       table->use_all_columns();
@@ -844,11 +841,7 @@ int mysql_update(THD *thd,
 err:
   delete select;
   free_underlaid_joins(thd, select_lex);
-  if (table->key_read)
-  {
-    table->key_read=0;
-    table->file->extra(HA_EXTRA_NO_KEYREAD);
-  }
+  table->set_keyread(FALSE);
   thd->abort_on_warning= 0;
   DBUG_RETURN(1);
 }