Re: [GENERAL] Unlogged Crash Detection

On 2017-08-29 20:19:52 +0900, Michael Paquier wrote:
> On Tue, Aug 29, 2017 at 6:06 PM, Gersner <gersner@gmail.com> wrote:
> > I see, interesting.
>
> Please do not top-post. This is not the recommended way of dealing
> with threads on this mailing list.
>
> > We have lots of unlogged tables, upon a crash we want to create a
> > feedback/alert that data disappeared.
> >
> > Not very familiar with the internal structure, but is it possible to
> > identify if the current table is the INIT_FORKNUM?
>
> Using pg_relation_filepath, you can know the path to a relation file
> on disk. So a simple idea would be to use pg_read_binary_file with the
> path of the file and the path of the init fork, which is suffixed with
> "_init", and then a comparison between both. If the data read is the
> same, the relation has been untouched.

Huh, but that's not particularly meaningful, is it? That'll just as well
be the case for a freshly created relation, no?

- Andres