Re: Add LSN along with offset to error messages reported for WAL file read/write/validate header failures

On Tue, Dec 06, 2022 at 04:27:50PM +0900, Kyotaro Horiguchi wrote:
> At Mon, 5 Dec 2022 10:03:55 +0900, Michael Paquier <michael@paquier.xyz> wrote in 
>> Hence I would tend to let XLogFromFileName do the job, while having a
>> SQL function that is just a thin wrapper around it that returns the
>> segment TLI and its number, leaving the offset out of the equation as
>> well as this new XLogIdFromFileName().
> 
> I don't think it could be problematic that the SQL-callable function
> returns a bogus result for a wrong WAL filename in the correct
> format. Specifically, I think that the function may return (0/0,0) for
> "000000000000000000000000" since that behavior is completely
> harmless. If we don't check logid, XLogFromFileName fits instead.

Yeah, I really don't think that it is a big deal either:
XLogIdFromFileName() just translates what it receives from the
caller for the TLI and the segment number.

> (If we assume that the file names are typed in letter-by-letter, I
>  rather prefer to allow lower-case letters:p)

Yep, makes sense to enforce a compatible WAL segment name if we can.
--
Michael