| From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
|---|---|
| To: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
| Cc: | Marco Nenciarini <marco(dot)nenciarini(at)2ndquadrant(dot)it>, Robert Haas <robertmhaas(at)gmail(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Gabriele Bartolini <gabriele(dot)bartolini(at)2ndquadrant(dot)it>, desmodemone <desmodemone(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Proposal: Incremental Backup |
| Date: | 2014-08-12 14:30:00 |
| Message-ID: | 20140812143000.GA18223@awork2.anarazel.de |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2014-08-12 10:25:21 -0300, Claudio Freire wrote:
> On Tue, Aug 12, 2014 at 6:41 AM, Marco Nenciarini
> <marco(dot)nenciarini(at)2ndquadrant(dot)it> wrote:
> > To declared two files identical they must have same size,
> > same mtime and same *checksum*.
>
> Still not safe. Checksum collisions do happen, especially in big data sets.
If you use an appropriate algorithm for appropriate amounts of data
that's not a relevant concern. You can easily do different checksums for
every 1GB segment of data. If you do it right the likelihood of
conflicts doing that is so low it doesn't matter at all.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Kevin Grittner | 2014-08-12 14:39:25 | Re: delta relations in AFTER triggers |
| Previous Message | MauMau | 2014-08-12 14:29:58 | Re: [RFC] Should smgrtruncate() avoid sending sinval message for temp relations |