On Fri, Dec 18, 2009 at 9:51 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> Part of what I'm confused about (and what I think should be documented >> in a comment somewhere) is why we're using MVCC visibility in some >> places but not others. In particular, there seem to be some bits of >> the comment that imply that we do this for read but not for write, >> which seems really strange. It may or may not actually be strange, >> but I don't understand it. > > It is supposed to depend on whether you opened the blob for read only > or for read write. Please do not tell me that this patch broke that; > because if it did it broke pg_dump. > > This behavior is documented at least here: > http://www.postgresql.org/docs/8.4/static/lo-interfaces.html#AEN36338
Oh, I see. Thanks for the pointer. Having read that through, I can now say that the comments in the patch seem to imply that it attempted to preserve those semantics, but I can't swear that it did. I will take another look at it, but it might bear closer examination by someone with more MVCC-fu than myself. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
