Re: [HACKERS] GUC for cleanup indexes threshold.

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.

--
Peter Geoghegan