| From: | Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Craig Ringer <craig(at)2ndquadrant(dot)com>, Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Tianzhou Chen <tianzhouchen(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [HACKERS] Challenges preventing us moving to 64 bit transaction id (XID)? |
| Date: | 2017-11-28 00:30:09 |
| Message-ID: | CAD21AoDydRvJrkmRozcXeC-5cig7HsrYwEzRjNKE6toFWx8=DQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Nov 28, 2017 at 4:56 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Fri, Nov 24, 2017 at 5:33 AM, Alexander Korotkov
> <a(dot)korotkov(at)postgrespro(dot)ru> wrote:
>> pg_prune_xid makes sense only for heap pages. Once we introduce special
>> area for heap pages, we can move pg_prune_xid there and save some bytes in
>> index pages. However, this is an optimization not directly related to
>> 64-bit xids. Idea is that if we anyway change page format, why don't apply
>> this optimization as well? But if we have any doubts in this, it can be
>> removed with no problem.
>
> My first reaction is that changing the page format seems like a
> non-starter, because it would break pg_upgrade.
IIUC xid-lsn ranges patch[1] doesn't require the page format
conversion. Is there any reason we can not go on that way? FWIW, I've
rebased the patch to current HEAD.
[1] https://www.postgresql.org/message-id/5242F8BF.6010807%40vmware.com
Regards,
--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
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