On Tue, Mar 6, 2012 at 5:50 PM, Bruce Momjian <br...@momjian.us> wrote:
> One crazy idea would be to have a checksum _version_ number somewhere on > the page and in pg_controldata. When you turn on checksums, you > increment that value, and all new checksum pages get that checksum > version; if you turn off checksums, we just don't check them anymore, > but they might get incorrect due to a hint bit write and a crash. When > you turn on checksums again, you increment the checksum version again, > and only check pages having the _new_ checksum version. > > Yes, this does add additional storage requirements for the checksum, but > I don't see another clean option. If you can spare one byte, that gives > you 255 times to turn on checksums; after that, you have to > dump/reload to use the checksum feature. I like the idea very much actually. But I'll let you argue the case for using pd_pagesize_version for that with your esteemed colleagues. It would be pretty safe to just let it wrap. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
