Re: Improve verification of recovery_target_timeline GUC.

On Thu, Jan 23, 2025 at 02:53:39PM +0000, David Steele wrote:
> Currently check_recovery_target_timeline() converts any value that is not
> current, latest, or a valid integer to 0. So for example:
> 
> recovery_target_timeline = 'currrent'
> 
> results in the following error:
> 
> FATAL:  22023: recovery target timeline 0 does not exist

Indeed, that's confusing.  There is nothing telling you what's
actually wrong here, particularly if there is a typo of any kind in
the parameter.

> I discovered this while testing on Postgres versions < 12 where
> The tests are probably excessive but I needed something to show that the
> verification works as expected.

Even with your patch, specifying an incorrect name results in a
complaint about a timeline of 0.  Wouldn't it be better to strengthen
the parsing in check_recovery_target_timeline() and/or the error
message reported?
--
Michael