Tom Lane wrote: > Vlad Arkhipov <arhi...@dc.baikal.ru> writes: > > In a BEFORE UPDATE trigger I need to know whether the row was previously > > modified by this transaction. Is it safe to use xmin and txid_current() > > for this purpose (xmin is 32-bit txid type but txid_current() returns > > 64-bit bigint). > > > IF OLD.xmin = txid_current() THEN > > Comparing to txid_current() mod 2^32 would probably work,
I think we should be setting the initial epoch to something other than zero. That way, some quick testing would have revealed this problem immediately. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers