Re: CLUSTER, reform_and_rewrite_tuple(), and parallelism

On 2016-08-17 16:23:29 -0700, Peter Geoghegan wrote:
> On Wed, Aug 17, 2016 at 4:16 PM, Andres Freund  wrote:
> >> Does anyone have any ideas on how to:
> >>
> >> 1). Directly address the reform_and_rewrite_tuple() bottleneck.
> >
> > What part of is actually the expensive bit? It does a whole lot of
> > things. Forming/Deforming tuples, the hash lookups in
> > rewrite_heap_tuple(), ...?
> 
> Perhaps the attached svg "flamegraph" will give you some idea. This is
> based on the "perf cache-misses" event type.

Could you also provide a strace -ttt -T -c and a cpu cycles flamegraph?