Re: new heapcheck contrib module

On Wed, May 13, 2020 at 7:32 PM Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
> I agree that this (a test tool that exercises our code against
> arbitrarily corrupted data pages) is not going to work as a test that
> all buildfarm members run -- it seems something for specialized
> buildfarm members to run, or even something that's run outside of the
> buildfarm, like sqlsmith. Obviously such a tool would not be able to
> run against an assertion-enabled build, and we shouldn't even try.

I have a question about what you mean here by "arbitrarily."

If you mean that we shouldn't have the buildfarm run the proposed heap
corruption checker against heap pages full of randomly-generated
garbage, I tend to agree. Such a test wouldn't be very stable and
might fail in lots of low-probability ways that could require
unreasonable effort to find and fix.

If you mean that we shouldn't have the buildfarm run the proposed heap
corruption checker against any corrupted heap pages at all, I tend to
disagree. If we did that, then we'd basically be releasing a heap
corruption checker with very limited test coverage. Like, we shouldn't
only have negative test cases, where the absence of corruption
produces no results. We should also have positive test cases, where
the thing finds some problem...

At least, that's what I think.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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