Re: pg_clog error

terry(at)greatgulfhomes(dot)com writes:
> Every night I pull data from a legacy system. Last night for the first time
> I got the error message:
> FATAL 2: open of /usr/local/pgsql/data/pg_clog/0081 failed: No such file or
> directory

The cases of this that have been seen so far have been traced to
hardware problems, as far as we can tell. (The specific error message
arises from trying to look up the commit status of a transaction
number that is far beyond the range of transaction numbers actually
used so far in your installation --- ie, some tuple someplace contained
a garbaged transaction-number field.)

Since you later report that the error was not reproducible, I'm
wondering about bad RAM that intermittently drops bits. Might be
time to try some memory diagnostics.

regards, tom lane