Robert Haas <robertmh...@gmail.com> writes: > On Sun, Mar 16, 2014 at 10:45 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Well, it will result in padding space when you maxalign the length word, >> but I don't see why it wouldn't work; and it would certainly be no less >> efficient than what's there today.
> Well, the problem is with this: > /* Write the message length into the buffer. */ > if (!mqh->mqh_did_length_word) > { > res = shm_mq_send_bytes(mqh, sizeof(uint64), &nbytes, nowait, > &bytes_written); > If I change nbytes to be of type Size, and the second argument to > sizeof(Size), then it's wrong whenever sizeof(Size) % MAXIMUM_ALIGNOF > != 0. Well, you need to maxalign the number of bytes physically inserted into the queue. Doesn't shm_mq_send_bytes do that? Where do you do the maxaligning of the message payload data, when the payload is odd-length? I would have expected some logic like "copy N bytes but then advance the pointer by maxalign(N)". regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers