On Thu, Dec 16, 2010 at 16:22, Tom Lane <t...@sss.pgh.pa.us> wrote: > Tatsuo Ishii <is...@postgresql.org> writes: >> It seems psql(or libpq) connects to PostgreSQL twice when md5 auth is >> required. Here is a strace log on my Linux machine. Is there any >> reason for this? IMO frontend/backend protocol allows to send salt >> after receiving AuthenticationMD5Password using the same socket. So >> there's no reason to close the socket and make it again. It seems to >> be just waste of resource. > > The sequence of events is > > 1. psql attempts connection > 2. libpq receives md5 challenge, realizes it doesn't have password, fails > 3. psql collects password from user, tries again > 4. libpq successfully makes connection > > AFAICS the only alternatives to two connections are > > (A) Have psql demand a password from the user before it knows whether > one is needed. Nonstarter for obvious reasons. > > (B) Complicate the libpq API to the point where a partially open > connection could be held onto while we ask for a password. Very > messy, and could fail anyway if user takes more than auth_timeout > to enter the password, or enters the wrong password first time. > > Two connections are not really a problem IMO, so I would not be in favor > of kluging the API to the extent required by solution (B).
(B) could be as simple as a callback asking for it, though, couldn't it? That seems a lot simpler (at least in the API) than trying to support hanging on to half-connected connections. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
