Re: amcheck (B-Tree integrity checking tool) - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: amcheck (B-Tree integrity checking tool)
Date
Msg-id CAM3SWZRGycL9t9GSSQPb2L5Zaxt-4ZnrFi35FRghvdOeetWs-g@mail.gmail.com
Whole thread Raw
In response to Re: amcheck (B-Tree integrity checking tool)  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: amcheck (B-Tree integrity checking tool)
List pgsql-hackers
On Sat, Nov 19, 2016 at 6:45 PM, Robert Haas <robertmhaas@gmail.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



pgsql-hackers by date:

Previous
From: Robert Haas
Date:
Subject: Re: amcheck (B-Tree integrity checking tool)
Next
From: Fabien COELHO
Date:
Subject: Re: [PATCH] pgpassfile connection option