Le samedi 22 juin 2013 01:09:20, Jehan-Guillaume (ioguix) de Rorthais a écrit : > On 20/06/2013 03:25, Tatsuo Ishii wrote: > >> On Wed, Jun 19, 2013 at 8:40 PM, Tatsuo Ishii <is...@postgresql.org> wrote: > >>>> On Wed, Jun 19, 2013 at 6:20 PM, Stephen Frost <sfr...@snowman.net> wrote: > >>>>> * Claudio Freire (klaussfre...@gmail.com) wrote: > [...] > > >> The only bottleneck here, is WAL archiving. This assumes you can > >> afford WAL archiving at least to a local filesystem, and that the WAL > >> compressor is able to cope with WAL bandwidth. But I have no reason to > >> think you'd be able to cope with dirty-map updates anyway if you were > >> saturating the WAL compressor, as the compressor is more efficient on > >> amortized cost per transaction than the dirty-map approach. > > > > Thank you for detailed explanation. I will think more about this. > > Just for the record, I was mulling over this idea since a bunch of > month. I even talked about that with Dimitri Fontaine some weeks ago > with some beers :) > > My idea came from a customer during a training explaining me the > difference between differential and incremental backup in Oracle. > > My approach would have been to create a standalone tool (say > pg_walaggregate) which takes a bunch of WAL from archives and merge them > in a single big file, keeping only the very last version of each page > after aggregating all their changes. The resulting file, aggregating all > the changes from given WAL files would be the "differential backup". > > A differential backup resulting from a bunch of WAL between W1 and Wn > would help to recover much faster to the time of Wn than replaying all > the WALs between W1 and Wn and saves a lot of space. > > I was hoping to find some time to dig around this idea, but as the > subject rose here, then here are my 2¢!
something like that maybe :
./pg_xlogdump -b \
../data/pg_xlog/000000010000000000000001 \
../data/pg_xlog/000000010000000000000005| \
grep 'backup bkp' | awk '{print ($5,$9)}'
--
Cédric Villemain +33 (0)6 20 30 22 52
http://2ndQuadrant.fr/
PostgreSQL: Support 24x7 - Développement, Expertise et Formation
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