On 2020-Aug-25, Andres Freund wrote:
> Hi,
>
> On 2020-08-26 15:58:14 +1200, Thomas Munro wrote:
> > > --12.51%--compactify_tuples
> > > PageRepairFragmentation
> > > heap2_redo
> > > StartupXLOG
> >
> > I wonder if there is something higher level that could be done to
> > reduce the amount of compaction work required in the first place, but
> > in the meantime I'm very happy if we can improve the situation so much
> > with such a microscopic improvement that might eventually benefit
> > other sorting stuff...
>
> Another approach could be to not perform any sorting during recovery,
> instead including enough information in the WAL record to avoid doing a
> full blown PageRepairFragmentation during recovery.
Hmm, including the sorted ItemId array in the WAL record might make
sense to alleviate the qsort work ...
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
