Re: Does Postgres ever write to tables without file system timestamps getting updated?

On Jun 6, 2017, at 7:32 AM, Thorsten Schöning <tschoening(at)am-soft(dot)de> wrote:
>
> Obviously I wasn't clear enough: Postgres is not running and my
> problem is with files and their timestamps in the past. So regarding
> the timestamps the files didn't change for weeks and the files have
> the same size and timestamp in the source and my backup. But if I
> calculate hash sums of those files the results may differ, so rsync
> using checksums will back them up, although the files claim that they
> haven't changed for days/weeks.

You were clear, it's too early in the morning here.

You seem to be assuming that the files were changed close to the time you found the problem; as far as I can tell that's not actually true, they could have been changed back at the time of the file timestamps, and could have been out-of-sync for a while, right?

My suggestion to use pg_start_backup is irrelevant to the exact problem you're describing. The documentation for it does describe a good way to get a file-based backup, without stopping the server, and you might want to check into that. You could also look at pg_base_backup.

--
Scott Ribe
scott_ribe(at)elevated-dev(dot)com
(303) 722-0567