Re: Re: [COMMITTERS] pgsql: Map basebackup tablespaces using a tablespace_map file

On Tue, Jun 9, 2015 at 12:27 AM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:

>
> On 06/08/2015 11:16 AM, Amit Kapila wrote:
>>
>>
>> I have to retry that operation, but for me unlink hasn't deleted
>> the file on Windows, may be I am not doing properly, but in
>> anycase why we want to throw error for such a case, why
>> can't we just ignore and create a symlink with the same name.
>>
>
> 1. You realize that in Windows postgres, unlink is actually pgunlink(),
> right? See port.h. If your experiments weren't using that then they weren't
> testing the same thing.
>

Yes, I know that and was using the same version, but the
small problem in my test was that the file name that is used
for unlink was not same as that of actual file in directory, sorry
for the noise.

> 2. If the unlink fails and the file is still there (i.e. pretty much
> everything except the ENOENT case) then creation of the symlink is bound to
> fail anyway.
>
> I realize our existing code just more or less assumes that that
>> it's a symlink. I think we've probably been a bit careless there.
>>
>>
>> I agree with you that deleting unrelated file with the same name as
>> symlink is not the right thing to do, but not sure throwing error for
>> such a case is better either.
>>
>>
>>
>
> What else would you suggest?

I think Robert and Alvaro also seems to be inclined towards throwing
error for such a case, so let us do that way, but one small point is that
don't you think that similar code in destroy_tablespace_directories() under
label "remove_symlink:" should use similar logic?

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com