t3lib_DB debug_check_recordset for exec_SELECT_*
Syslog-Entries and or devlog-entries are written in function debug_check_recordset.
Altough functionality is already implemented, debug_check_recordset is not called from exec_SELECT-Querys because debug_check_recordset is called AFTER (!$this->sql_error()). So it never get's called.
So any error that occurs, will not be traced within debug_check_recordset. So this function at this point is usless.
Maybe providing a syslog entry within sql_error() would be a better approach because all sql-errors are then tracked within the syslog or errorlog.