Re: [Patch] Optimize dropping of relation buffers using dlist

On Thu, Dec 10, 2020 at 7:11 AM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> At Wed, 9 Dec 2020 16:27:30 +0530, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote in
> > On Wed, Dec 9, 2020 at 6:32 AM Kyotaro Horiguchi
> > > Mmm. At least btree doesn't need to call smgrnblocks except at
> > > expansion, so we cannot get to the optimized path in major cases of
> > > truncation involving btree (and/or maybe other indexes).
> > >
> >
> > AFAICS, btree insert should call smgrnblocks via
> > btree_xlog_insert->XLogReadBufferForRedo->XLogReadBufferForRedoExtended->XLogReadBufferExtended->smgrnblocks.
> > Similarly delete should also call smgrnblocks. Can you be bit more
> > specific related to the btree case you have in mind?
>
> Oh, sorry. I wrongly looked to non-recovery path. smgrnblocks is
> called during buffer loading while recovery. So, smgrnblock is called
> for indexes if any update happens on the heap relation.
>

Okay, so this means that we can get the benefit of optimization in
many cases in the Truncate code path as well even if we use 'cached'
flag? If so, then I would prefer to keep the code consistent for both
vacuum and truncate recovery code path.

--
With Regards,
Amit Kapila.