| From: | "Fujii Masao" <masao(dot)fujii(at)gmail(dot)com> |
|---|---|
| To: | "Robert Lor" <Robert(dot)Lor(at)sun(dot)com> |
| Cc: | "Alvaro Herrera" <alvherre(at)commandprompt(dot)com>, "Bruce Momjian" <bruce(at)momjian(dot)us>, "pgsql-hackers list" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: DTrace probes patch |
| Date: | 2008-12-18 03:26:33 |
| Message-ID: | 3f0b79eb0812171926p6f7d5623rbacb9cf769fd36e0@mail.gmail.com |
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| Thread: | |
| Lists: | pgsql-hackers |
Hi,
On Thu, Dec 18, 2008 at 4:49 AM, Robert Lor <Robert(dot)Lor(at)sun(dot)com> wrote:
> Alvaro Herrera wrote:
>>
>> But there are 5 callers of XLogWrite ... why aren't the other ones being
>> tracked too?
>>
>>
>
> This probe originally came from Simon, so it can't possibly be wrong :-)
>
> My understanding is that we only want to track the XLogWrite when advancing
> to the next buffer page, and if there is unwritten data in the new buffer
> page, that indicates no more empty WAL buffer pages available, but I may be
> wrong. I did some tests by adjusting wal_buffers, and I could observe this
> behavior, more calls to XLogWrite with smaller wal_buffers.
I understood your intention. But, I think that its function name is somewhat
confusing.
Regards,
--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
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