note 31521 deleted from function.mysql-insert-id by cmb

Note Submitter: treylane at example dot com ---- This might be obvious, but it tripped me up - be careful when using last_insert_id() with persistent connections - running last_insert_id() after a failed update/insert/etc will return the last insert id of the last successful update/insert made by that CONNECTION rather than 0 for the number of rows updated by the previous non-working query, and who knows what the last query run on that connection was.