Re: Avoiding pin scan during btree vacuum

On Thu, Oct 20, 2016 at 4:00 AM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Robert Haas wrote:
>> On Mon, Jan 4, 2016 at 10:30 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> >> This seems like a might subtle thing to backpatch. If we really want to
>> >> go there, ISTM that the relevant code should stew in an unreleased
>> >> branch for a while, before being backpatched.
>> >
>> > I'm definitely -1 on back-patching such a thing. Put it in HEAD for
>> > awhile. If it survives six months or so then we could discuss it again.
>>
>> I agree with Tom.
>
> Okay, several months have passed with this in the development branch and
> now seems a good time to backpatch this all the way back to 9.4.
>

Are you talking about commit -
3e4b7d87988f0835f137f15f5c1a40598dd21f3d? If yes, do we want to
retain this code in its current form under define UNUSED, is there any
advantage of same. Another point is that won't this commit make
information in xl_btree_vacuum redundant, so shouldn't we remove it
usage during WAL writing as well?

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com