Robert Haas <robertmh...@gmail.com> writes: > On Fri, Oct 14, 2016 at 10:50 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> I dunno. If the failure were very low-probability, you could maybe live >> with that behavior, but I'm not sure it is. Presumably the Python >> interpreter loop is taking that lock once per statement (at least), so >> that it can tell if there's something to do. That'd suggest that the >> fraction of time in which the lock is held is not negligible.
> I'm not sure that kibitzing the way the Python developers chose to > handle this is very helpful. Our job to use the APIs they've exposed, > not second-guess how they implemented them. The comment suggests that > the Python team thought that this would be reliable enough to be > acceptable, and I think we should assume they're right. Well, the comment implies strongly that they expect it to be used in situations where the signal handler would execute on a different thread from the python interpreter loop. So the proposed Postgres usage is really not within the intended scope of use of the function. > Sitting on our hands gets us nowhere. I'm not sure where I said to sit on our hands. I pointed to the Python trace callback as a likely implementation that would not suffer from this problem --- and wouldn't require us to invent safe ways to install extension callback hooks in our signal handlers, which is not a trivial problem either. 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