Re: Re: [BUGS] BUG #4566: pg_stop_backup() reports incorrect STOP WAL LOCATION - Mailing list pgsql-hackers

From Fujii Masao
Subject Re: Re: [BUGS] BUG #4566: pg_stop_backup() reports incorrect STOP WAL LOCATION
Date
Msg-id 3f0b79eb1002152119m2be4a818x4b72172d27892f@mail.gmail.com
Whole thread Raw
In response to Re: Re: [BUGS] BUG #4566: pg_stop_backup() reports incorrect STOP WAL LOCATION  (Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>)
Responses Re: Re: [BUGS] BUG #4566: pg_stop_backup() reports incorrect STOP WAL LOCATION
List pgsql-hackers
On Fri, Feb 5, 2010 at 9:08 AM, Takahiro Itagaki
<itagaki.takahiro@oss.ntt.co.jp> wrote:
>
> Fujii Masao <masao.fujii@gmail.com> wrote:
>
>> On Fri, Dec 5, 2008 at 11:41 PM, Randy Isbell <jisbell@cisco.com> wrote:
>> > An inconsistency exists between the segment name reported by
>> > pg_stop_backup() and the actual WAL file name.
>> >
>> > START WAL LOCATION: 10/FE1E2BAC (file 0000000200000010000000FE)
>> > STOP WAL LOCATION: 10/FF000000 (file 0000000200000010000000FF)
>
>> But it was rejected because its change might break the existing app.
>
> It might break existing applications if it returns "FE" instead of "FF",
> but never-used filename surprises users. (IMO, the existing apps probably
> crash if "FF" returned, i.e, 1/256 of the time.)
>
> Should it return the *next* reasonable log filename instead of "FF"?
> For example, 000000020000002000000000 for the above case.

Here is the patch that avoids a nonexistent file name, according to
Itagaki-san's suggestion. If we are crossing a logid boundary, the
next reasonable file name is used instead of a nonexistent one.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center

Attachment

pgsql-hackers by date:

Previous
From: KaiGai Kohei
Date:
Subject: Re: CommitFest Status Summary - 2010-02-14
Next
From: Tom Lane
Date:
Subject: Re: LISTEN/NOTIFY and notification timing guarantees