The SQL spec does not say anything on this respect (that I can find). It only talks of "FOR UPDATE" and "FOR READ ONLY". However, because the FK code uses SPI to do the locking, we definitely have to expose the funcionality through SQL. So I think we need a new clause, which I propose to be "FOR SHARE".
MySQL uses LOCK IN SHARE MODE:
http://dev.mysql.com/doc/mysql/en/InnoDB_locking_reads.html
---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend