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.
- Heikki
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