Thomas Munro wrote: > On Tue, Jun 2, 2015 at 9:30 AM, Alvaro Herrera <alvherre@xxxxxxxxxxxxxxx> wrote: > > My guess is that the file existed, and perhaps had one or more pages, > > but the wanted page doesn't exist, so we tried to read but got 0 bytes > > back. read() returns 0 in this case but doesn't set errno. > > > > I didn't find a way to set things so that the file exists but is of > > shorter contents than oldestMulti by the time the checkpoint record is > > replayed. > > I'm just starting to learn about the recovery machinery, so forgive me > if I'm missing something basic here, but I just don't get this. As I > understand it, offsets/0046 should either have been copied with that > page present in it if it existed before the backup started (apparently > not in this case), or extended to contain it by WAL records that come > after the backup label but before the checkpoint record that > references it (also apparently not in this case). Exactly --- that's the spot at which I am, also. I have had this spinning in my head for three days now, and tried every single variation that I could think of, but like you I was unable to reproduce the issue. However, our customer took a second base backup and it failed in exactly the same way, module some changes to the counters (the file that didn't exist was 004B rather than 0046). I'm still at a loss at what the failure mode is. We must be missing some crucial detail ... -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
