Hi, My problem is that if I try to update more than one row in a table like > UPDATE mytable SET something = 84 WHERE not_unique_col = 41; in two concurrent transactions, it can result in a deadlock if the two UPDATEs visit the rows in a different order. The same applies, if I try to > SELECT * FROM mytable WHERE not_unique_col = 41 FOR UPDATE; But what if I try like > SELECT * FROM mytable > WHERE not_unique_col = 41 ORDER BY pri_key ASC FOR UPDATE; and do the UPDATE after this? It should never lead to a deadlock, assuming the rows selected FOR UPDATE are locked in the order as they are returned. But is that true? Are the rows selected FOR UPDATE locked in the same order as they are returned (as specified in ORDER BY)? I'm not quite sure (though I tested it on a small table and it looked fine), because I (or should I say Google) could not find even one page on postgresql.org where this row-level deadlock situation had been solved... I could only find Tom Lane's post, where he admitted that this can lead to a deadlock: http://archives.postgresql.org/pgsql-general/2004-11/msg01372.php I don't believe that no one thought of this solution before, so there must be something wrong with it... :) Regards, Panther PS: Sorry if this will be a double-post, but it looks like my previous mail was lost somewhere... _______________________________________________________________ Ne csak a lakást nézze, hanem a környéket is! Válogasson több ezer ingatlanból légifotós-kereső segítségével! http://ad.adverticum.net/b/cl,1,6022,135082,205798/click.prm
