On Mon, Jun 06, 2022 at 04:23:34PM +0900, Michael Paquier wrote:
> On Sat, Jun 04, 2022 at 08:42:33PM -0500, Justin Pryzby wrote:
> > The fix seems to be to CHECK_FOR_INTERRUPTS() within multi_sort_compare().
> > That would supercede the other two CHECK_FOR_INTERRUPTS I'd proposed, and
> > handle mcv, depends, and ndistinct all at once.
>
> Hmm. I have to admit that adding a CFI() in multi_sort_compare()
> stresses me a bit as it is dependent on the number of rows involved,
> and it can be used as a qsort routine.
That's exactly the problem for which I showed a backtrace - it took 10s of
seconds to do qsort, which is (uh) a human timescale and too long to be
unresponsive, even if I create on a table with many rows a stats object with a
lot of columns and a high stats target.