On Thu, Apr 23, 2015 at 10:42:59AM +0300, Heikki Linnakangas wrote: > On 04/22/2015 09:24 PM, Robert Haas wrote: > >>I would feel safer if we added a completely new "epoch" counter to the page > >>>header, instead of reusing LSNs. But as we all know, changing the page > >>>format is a problem for in-place upgrade, and takes some space too. > >Yeah. We have a serious need to reduce the size of our on-disk > >format. On a TPC-C-like workload Jan Wieck recently tested, our data > >set was 34% larger than another database at the beginning of the test, > >and 80% larger by the end of the test. And we did twice the disk > >writes. See "The Elephants in the Room.pdf" at > >https://sites.google.com/site/robertmhaas/presentations > > Meh. Adding an 8-byte header to every 8k block would add 0.1% to the > disk size. No doubt it would be nice to reduce our disk footprint, > but the page header is not the elephant in the room.
Agreed. Are you saying we can't find a way to fit an 8-byte value into the existing page in a backward-compatible way? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers