Re: [PATCH] V3: Idle in transaction cancellation

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Greg Smith <greg@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@commandprompt.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Kevin Grittner <kevin.grittner@wicourts.gov>
Date: 2010-12-16T20:18:58Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> Hmm.  It's seeming to me that what we want to do is something like this:

> 1. If an error is thrown while DoingCommandRead, it gets upgraded to
> FATAL.  I don't think we have much choice about this because, per your
> previous comments, we can't longjmp() here without risking protocol
> breakage, and we certainly can't return from an elog(ERROR) or
> ereport(ERROR).

Um, if that's the ground rules then we have no advance over the current
situation.

I guess you misunderstood what I said.  What I meant was that we cannot
longjmp *out to the outer level*, ie we cannot take control away from
the input stack.  We could however have a TRY block inside the interrupt
handler that catches and handles (queues) any errors occurring during
transaction abort.  As long as we eventually return control to openssl
I think it should work.  (Hm, but I wonder whether there are any hard
timing constraints in the ssl protocol ... although hopefully xact abort
won't ever take long enough that that's a real problem.)

			regards, tom lane