Re: Assert failure on running a completed portal again

Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp> writes:
> I notice that the following Assert in PortalRun fails when a same portal is
> executed more than once by an Execute message whose "max number of rows"
> is specified to zero, that is, "no limit".

> /* Set run_once flag. Shouldn't be clear if previously set. */
> Assert(!portal->run_once || run_once);
> portal->run_once = run_once;

Hmm. It's fairly hard to tell what was meant there, because
(a) there is exactly zero documentation of what run_once means
(b) that comment is opaque and doesn't appear to describe the
code behavior anyway.

> I believe the server should return CommanComplete normally in this case.
> his can be fixed by not setting execute_is_fetch flag (run_once as the result)
> when the portal is already completed since no rows will be fetched in this case.

Don't like this much. I'm not sure I believe any part of this
approach to deciding whether the portal is "run once". In any
case, a proper fix for this needs to include actually documenting
what that field means and does.

regards, tom lane