Re: Re: [BUGS] BUG #4566: pg_stop_backup() reports incorrect STOP WAL LOCATION

On Fri, Feb 5, 2010 at 9:08 AM, Takahiro Itagaki
<itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp> wrote:
>
> Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>
>> On Fri, Dec 5, 2008 at 11:41 PM, Randy Isbell <jisbell(at)cisco(dot)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