Excerpts from Kevin Grittner's message of lun jun 25 14:50:54 -0400 2012: > One fine point regarding before and after images -- if a value > doesn't change in an UPDATE, there's no reason to include it in both > the BEFORE and AFTER tuple images, as long as we have the null > column bitmaps -- or some other way of distinguishing unchanged from > NULL. (This could be especially important when the unchanged column > was a 50 MB bytea.)
Yeah, probably the best is to have the whole thing in BEFORE, and just send AFTER values for those columns that changed, and include the 'replace' bool array (probably packed as a bitmap), so that the update can be trivially constructed at the other end just like in heap_modify_tuple. -- Álvaro Herrera <alvhe...@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
