From: | Andres Freund <andres(at)anarazel(dot)de> |
---|---|
To: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Thom Brown <thom(at)linux(dot)com>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, Fabrízio Mello <fabriziomello(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Error with index on unlogged table |
Date: | 2015-12-10 07:57:38 |
Message-ID: | EA7EE062-11CB-4FD3-B36C-EA2CB97633BE@anarazel.de |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On December 10, 2015 5:02:27 AM GMT+01:00, Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote:
>On Wed, Dec 9, 2015 at 9:07 PM, Andres Freund <andres(at)anarazel(dot)de>
>wrote:
>> On 2015-12-09 21:03:47 +0900, Michael Paquier wrote:
>>> Oh, OK. I didn't read though your lines correctly. So you basically
>>> mean that we would look at the init files that are on disk, and
>check
>>> if they are empty. If they are, we simply use XLogReadBufferExtended
>>> to fetch the INIT_FORKNUM content and fill in another buffer for the
>>> MAIN_FORKNUM. More or less right?
>>
>> We would not just do so if they're empty, we would just generally
>copy the file
>> via shared buffers, instead of copy_file(). But we'd get the file
>size
>> from the filesystem (which is fine, we make sure it is correct during
>> replay).
>
>So, this suggestion is basically implementing the reverse operation of
>GetRelationPath() to be able to rebuild a RelFileNode from scratch and
>then look at the shared buffers needed. Isn't it a bit brittle for
>back-branches? RelFileNode stuff is available easily through records
>when replaying individually FPIs, but not really in this code path.
Oh, sorry. In definitely not thinking about doing this for the back branches. That was more musing about a way to optimize this.
Andres
---
Please excuse brevity and formatting - I am writing this on my mobile phone.
From | Date | Subject | |
---|---|---|---|
Next Message | Andres Freund | 2015-12-10 08:34:07 | Re: Rework the way multixact truncations work |
Previous Message | Kyotaro HORIGUCHI | 2015-12-10 07:30:05 | Re: [PROPOSAL] VACUUM Progress Checker. |