Function sub_select_cache

sql/sql_select.cc:24444–24500

*/ 

enum_nested_loop_state
sub_select_cache(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
{
  enum_nested_loop_state rc;
  JOIN_CACHE *cache= join_tab->cache;
  int err;
  DBUG_ENTER("sub_select_cache");

  /*
    This function cannot be called if join_tab has no associated join
    buffer
  */
  DBUG_ASSERT(cache != NULL);

  join_tab->cache->reset_join(join);

  if (end_of_records)
  {
    rc= cache->join_records(FALSE);
    if (rc == NESTED_LOOP_OK || rc == NESTED_LOOP_NO_MORE_ROWS ||
        rc == NESTED_LOOP_QUERY_LIMIT)
      rc= sub_select(join, join_tab, end_of_records);
    DBUG_RETURN(rc);
  }
  if (unlikely(join->thd->check_killed()))
  {
    /* The user has aborted the execution of the query */
    DBUG_RETURN(NESTED_LOOP_KILLED);
  }
  join_tab->jbuf_loops_tracker->on_scan_init();

  if (!(err= test_if_use_dynamic_range_scan(join_tab)))
  {
    if (!cache->put_record())
      DBUG_RETURN(NESTED_LOOP_OK); 
    /* 
      We has decided that after the record we've just put into the buffer
      won't add any more records. Now try to find all the matching 
      extensions for all records in the buffer.
    */ 
    rc= cache->join_records(FALSE);
    DBUG_RETURN(rc);
  }

  if (err < 0)
    DBUG_RETURN(NESTED_LOOP_ERROR);

  /*
     TODO: Check whether we really need the call below and we can't do
           without it. If it's not the case remove it.
  */ 
  rc= cache->join_records(TRUE);
  if (rc == NESTED_LOOP_OK || rc == NESTED_LOOP_NO_MORE_ROWS ||
      rc == NESTED_LOOP_QUERY_LIMIT)
    rc= sub_select(join, join_tab, end_of_records);
  DBUG_RETURN(rc);
}