| From: | Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru> |
|---|---|
| To: | Michael Paquier <michael(at)paquier(dot)xyz>, 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: | 2018-11-19 05:48:06 |
| Message-ID: | 49518b48-2036-5e43-1818-0f594e375e76@postgrespro.ru |
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| Lists: | pgsql-hackers |
On 16.11.2018 11:23, Michael Paquier wrote:
> On Thu, Nov 15, 2018 at 06:12:38PM +0900, Kyotaro HORIGUCHI wrote:
>> This patch eliminates unnecessary copying that was done for
>> non-continued records. Now the return value of XLogReadRecord
>> directly points into page buffer holded in XLogReaderStats. It is
>> safe because no caller site uses the returned pointer beyond the
>> replacement of buffer content at the next call to the same
>> function.
>
> I was looking at this patch, and shouldn't we worry about compatibility
> with plugins or utilities which look directly at what's in readRecordBuf
> for the record contents? Let's not forget that the contents of
> XLogReaderState are public.
According to my experience, I clarify some comments to avoid this
mistakes in the future (see attachment).
--
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company
| Attachment | Content-Type | Size |
|---|---|---|
| 0001-Some-clarifications-on-readRecordBuf-comments.patch | text/x-patch | 1.7 KB |
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