On Friday, January 11, 2013 11:09 PM Simon Riggs wrote: On 11 January 2013 17:08, Amit kapila <amit.kap...@huawei.com> wrote:
>>> Just reviewing the patch now, making more sense with comments added. > >>>In heap_delta_encode() do we store which columns have changed? > >> Not the attribute bumberwise, but offsetwise it is stored. > (Does that mean "numberwise"??) Yes. > Can we identify which columns have changed? i.e. 1st, 3rd and 12th columns? As per current algorithm, we can't as it is based on offsets. What I mean to say is that the basic idea to reconstruct tuple during recovery is copy data from old tuple offset-wise (offsets stored in encoded tuple) and use new data (modified column data) from encoded tuple directly. So we don't need exact column numbers. With Regards, Amit Kapila. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
