Re: [PATCH] XLogReadRecord returns pointer to currently read page

From: Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru>
To: Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
Cc: hlinnaka(at)iki(dot)fi, pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] XLogReadRecord returns pointer to currently read page
Date: 2018-10-26 06:43:14
Message-ID: ea3dca6a-b898-e7a8-dcfa-b3ad227a6349@postgrespro.ru
Views: Raw Message | Whole Thread | Download mbox
Thread:
Lists: pgsql-hackers

On 26.10.2018 10:33, Kyotaro HORIGUCHI wrote:
> Hello.
>
> At Tue, 23 Oct 2018 10:25:27 +0500, Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru> wrote in <2553f2b0-0e39-eb0e-d382-6c0ed08ca8ae(at)postgrespro(dot)ru>
>>
>> On 23.10.2018 0:53, Heikki Linnakangas wrote:
>>> I'd expect the decompression to read from the on-disk buffer, and
>>> unpack to readRecordBuf, I still don't see a need to copy the packed
>>> record to readRecordBuf. If there is a need for that, though, the
>>> patch that implements the packing or compression can add the memcpy()
>>> where it needs it.
>>
>> I agree with it. Eventually, placement of the WAL-record can be
>> defined by comparison the record, readBuf and readRecordBuf pointers.
>> In attachment new version of the patch.
>
> This looks quite clear and what it does is reasonable to me.
> Applies cleanly on top of current master and no regression seen.
>
>
> Just one comment. This patch leaves the following code.
>
> > /* Record does not cross a page boundary */
> > if (!ValidXLogRecord(state, record, RecPtr))
> > goto err;
> >
> > state->EndRecPtr = RecPtr + MAXALIGN(total_len);
> !>
> > state->ReadRecPtr = RecPtr;
> > }
>
> The empty line (marked by '!') looks a bit too much standing out
> after this patch. Could you remove the line? Then could you
> transpose the two assignments if you don't mind?

Thanks, see attachment.

--
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company

Attachment Content-Type Size
0001-WAL-record-buffer-pointer-fix.patch text/x-patch 2.1 KB

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Fabien COELHO 2018-10-26 07:21:51 Re: libpq host/hostaddr/conninfo inconsistencies
Previous Message 임명규 2018-10-26 06:09:56 RE: COPY FROM WHEN condition