Re: [RFC] Incremental backup v2: add backup profile to base backup

Il 06/10/14 17:55, Robert Haas ha scritto:
> On Mon, Oct 6, 2014 at 11:51 AM, Marco Nenciarini
> <marco(dot)nenciarini(at)2ndquadrant(dot)it> wrote:
>> I agree that a full backup does not need to include a profile.
>>
>> I've added the option to require the profile even for a full backup, as
>> it can be useful for backup softwares. We could remove the option and
>> build the profile only during incremental backups, if required. However,
>> I would avoid the needing to scan the whole backup to know the size of
>> the recovered data directory, hence the backup profile.
>
> That doesn't seem to be buying you much. Calling stat() on every file
> in a directory tree is a pretty cheap operation.
>

In case of incremental backup it is not true. You have to read the delta
file to know the final size. You can optimize it putting this
information in the first few bytes, but in case of compressed tar format
you will need to scan the whole archive.

Regards,
Marco

--
Marco Nenciarini - 2ndQuadrant Italy
PostgreSQL Training, Services and Support
marco(dot)nenciarini(at)2ndQuadrant(dot)it | www.2ndQuadrant.it