Re: PITR backup history files with identical 2nd part file names

Rafael Martinez <r.m.guerrero@usit.uio.no> writes:
> After upgrading to 8.3.9 and moving some our PostgreSQL clusters to a
> new server yesterday, we have experienced a strange thing this past night.

> All PITR backup history files created when running a PITR base backup on
> all PostgreSQL clusters running in this new server (at different hours
> during the night) got an identical 2nd part file name.

> <24 digits>.00000020.backup e.g.000000020000020800000060.00000020.backup

I think this is normal behavior now, if you have an unloaded server.
pg_start_backup now forces a segment switch, so if nothing much else is
happening it's quite likely that the recorded start point will be the
beginning of the WAL segment (plus the page header size).

> Is it normal to get the same 2nd part of the file name all the time? How
> is this value generated?

It's just the current offset within the current WAL segment.
        regards, tom lane