On Sun, Aug 2, 2020 at 7:18 PM Merlin Moncure <mmonc...@gmail.com> wrote: > > Hackers, > > I have a situation that I am observing where dblink_is_busy returns 1 > even though the connection is long gone. tcp keepalives are on and > the connection has been dead for several hours. Looking at the call > for dblink_is_busy, I see that it is a thin wrapper to PQusBusy(). > If I attempt to call dblink_get_result(), the result comes back with > an error mesage, 'invalid socket'. This however is not helpful since > there is no way to probe for dead connections in dblink that appears > to be 100% reliable. My workaround that I had been relying on was to > call dblink_get_notify twice, which for some weird reason forced the > connection error to the surface. However for whatever reason, that is > not working here. > > In cases the connection was cancelled via dblink_cancel_query(), so in > some scenarios connections cancelled that way seem to become 'stuck'. > Any thoughts on this?
Correction, keepalives are probably not on, because dblink does not have an option to set them. Also, it looks like dblink_is_busy() calls pqConsumeInput without checking the error code. Is that safe? merlin
