Re: [HACKERS] GUC for cleanup indexes threshold.

Greetings Peter,

* Peter Geoghegan (pg(at)bowt(dot)ie) wrote:
> On Sat, Jan 6, 2018 at 2:20 PM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> >> > IIRC the patches that makes the cleanup scan skip has a problem
> >> > pointed by Peter[1], that is that we stash an XID when a btree page is
> >> > deleted, which is used to determine when it's finally safe to recycle
> >> > the page. Yura's patch doesn't have that problem?
> >> >
> >> > [1] https://www.postgresql.org/message-id/CAH2-Wz%3D1%3Dt5fcGGfarQGcAWBqaCh%2BdLMjpYCYHpEyzK8Qg6OrQ%40mail.gmail.com
>
> > Masahiko Sawada, if this patch isn't viable or requires serious rework
> > to be acceptable, then perhaps we should change its status to 'returned
> > with feedback' and you can post a new patch for the next commitfest..?
>
> I believe that the problem that I pointed out with freezing/wraparound
> is a solvable problem. If we think about it carefully, we will come up
> with a good solution. I have tried to get the ball rolling with my
> pd_prune_xid suggestion. I think it's important to not lose sight of
> the fact that the page deletion/recycling XID thing is just one detail
> that we need to think about some more.
>
> I cannot fault Sawada-san for waiting to hear other people's views
> before proceeding. It really needs to be properly discussed.

Thanks for commenting!

Perhaps it should really be in Needs review state then..?

Either way, thanks again for the clarification and hopefully this will
revive the discussion.

Stephen