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

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<mailto: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<mailto: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.

>I also think it would probably be worthwhile to support this in tar format as well, but I guess that's a separate patch really. There's really no reason we should't support wal streaming into a separate tar file. But - separate issue.

Sure. I will prepare a separate patch for the same and submit it in the next commit fest.

Regards,
Hari babu.