Re: New option for pg_basebackup, to specify a different directory for pg_xlog

On Sat, Nov 16, 2013 at 2:27 PM, Haribabu kommi
<haribabu(dot)kommi(at)huawei(dot)com> wrote:
> on 15 November 2013 17:26 Magnus Hagander wrote:
>
>>On Fri, Nov 15, 2013 at 12:10 PM, Haribabu kommi
>> <haribabu(dot)kommi(at)huawei(dot)com> wrote:
>
>>On 14 November 2013 23:59 Fujii Masao wrote:
>>> On Thu, Nov 14, 2013 at 9:08 PM, Haribabu kommi
>>> <haribabu(dot)kommi(at)huawei(dot)com> wrote:
>>> > Please find attached the patch, for adding a new option for
>>> > pg_basebackup, to specify a different directory for pg_xlog.
>>>>
>>> Sounds good! Here are the review comments:
>>>> Don't we need to prevent users from specifying the same directory in
>>>> both --pgdata and --xlogdir?
>
>>>I feel no need to prevent, even if user specifies both --pgdata and
>>> --xlogdir as same directory
>>>all the transaction log files will be created in the base directory
>>> instead of pg_xlog directory.
>
>
>
>>Given how easy it would be to prevent that, I think we should. It would be
>> an easy misunderstanding to specify that when you actually want it in
>> <wherever>/pg_xlog. Specifying that would be redundant in the first place,
>> but people ca do that, but it
>
>>would also be very easy to do it by mistake, and you'd end up with
>> something that's really bad, including a recursive symlink.
>
>
>
> Presently with initdb also user can specify both data and xlog directories
> as same.
>
> To prevent the data directory and xlog directory as same, there is a way in
> windows (_fullpath api) to get absolute path from a relative path, but I
> didn’t get any such possibilities in linux.
>
> I didn’t find any other way to check it, if anyone have any idea regarding
> this please let me know.

What about make_absolute_path() in miscinit.c?

Regards,

--
Fujii Masao