On Mon, May 21, 2012 at 12:43 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Mon, May 21, 2012 at 12:23 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> If we were sure that the kernel error was permanent, then this argument >>> would be moot: the data is gone already. The scary thought here is that >>> it might be a transient error, such as a not-always-repeatable kernel >>> bug. In that case, zeroing the page would indeed lose data that had >>> been recoverable before. > >> Yeah, and in fact I think that's probably not a terribly remote >> scenario. Also, if you're running on dying hardware, you really do >> NOT want to force the kernel to write a whole bunch of pages back to >> the dying disk in the midst of trying to pg_dump it before it falls >> over. You just want to read what you can of what's there now. > > Hm? zero_damaged_pages doesn't cause the buffer to be marked dirty, > so I dunno where these alleged writes are coming from.
I'm not sure either, but I'm pretty sure I've seen at least one case where turning it on caused a whole lotta data to disappear. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
