Re: rare avl shutdown slowness (related to signal handling)

On Tue, Apr 7, 2015 at 2:32 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> That seems like (a) a hack, and (b) not likely to solve the problem
> completely, unless you leave interrupts held throughout proc_exit(),
> which would create all sorts of opportunities for corner case bugs
> during on_proc_exit hooks.
>

Hmm, looks like proc_exit() already taken care of this by setting
proc_exit_inprogress and StatementCancelHandler() respects it.
Actually, in quickdie(), I found a similar practice for the same
reason:

/*
* Prevent interrupts while exiting; though we just blocked signals that
* would queue new interrupts, one may have been pending. We don't want a
* quickdie() downgraded to a mere query cancel.
*/
HOLD_INTERRUPTS();
I do feel that we have too many functions instructing how to handle
interrupts and they are subtle - I just found a new friend
HOLD_CANCEL_INTERRUPTS :-(

Regards,
Qingqing