Re: "could not read block 0... " error followed by "database does not exist"

Janet S Jacobsen <JSJacobsen@lbl.gov> writes:
> Hi.  What I see when I do ls on the current (corrupt)
> $PGDATA/global is

> ...
> - rw------- 1 jsjacobs deepsky     0 Feb  8 18:51 1262
> ...
> -rw------- 1 jsjacobs deepsky   602 Feb 12 17:42 pg_auth
> -rw------- 1 jsjacobs deepsky  8192 Feb 12 17:42 pg_control
> -rw------- 1 jsjacobs deepsky     0 Feb 12 17:42 pg_database
> -rw------- 1 jsjacobs deepsky 10927 Feb 12 21:57 pgstat.stat

Looks about as I'd expect from your description.  Something clobbered
1262, and then the "flat" file pg_database got updated from that.
You might want to look around at what was happening Feb 8 18:51.

> I have a pgdump from a month ago.  Are you saying to restore
> that to a different location and then copy over
> $PGDATA/global/1262?  Do I also need to copy over
> $PGDATA/global/pg_database?

Right on both.  Of course, it'd be a good idea to first make a backup of
what you have in $PGDATA now (all of it) --- you want to be able to get
back to where you are if this makes things worse.

            regards, tom lane