Re: amcheck (B-Tree integrity checking tool)

On Sat, Nov 19, 2016 at 6:45 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> What do you think about new argument with default vs. GUC? I guess
>> that the GUC might be a lot less of a foot-gun. We might even give it
>> a suitably scary name, to indicate that it will make the server PANIC.
>> (I gather that you don't care about other aspects of verbosity -- just
>> about the ability to make amcheck PANIC in the event of an invariant
>> violation without recompiling it.)
>
> Yikes. I don't think I want to expose any kind of API that lets the
> user PANIC the server. A value < ERROR sounds far more reasonable
> than a value > ERROR.

In general, I don't want to get into the business of reasoning about
how well we can limp along when there is a would-be error condition
within amcheck. Once "the impossible" has actually occurred, it's very
difficult to reason about what still works. Also, I actually agree
that making it possible for the tool to force a PANIC through a
user-visible interface is a bad idea.

Maybe we should just leave it as it is -- experts can recompile the
tool after modifying it to use an elevel that is != ERROR (the thing I
mention about elevel < ERROR is already documented in code comments).
If that breaks, they get to keep both halves.

--
Peter Geoghegan