Re: new heapcheck contrib module

> On Oct 26, 2020, at 6:37 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Fri, Oct 23, 2020 at 2:04 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Seems to work, so I pushed it (after some compulsive fooling
>> about with whitespace and perltidy-ing). It appears to me that
>> the code coverage for verify_heapam.c is not very good though,
>> only circa 50%. Do we care to expend more effort on that?
>
> There are two competing goods here. On the one hand, more test
> coverage is better than less. On the other hand, finicky tests that
> have platform-dependent results or fail for strange reasons not
> indicative of actual problems with the code are often judged not to be
> worth the trouble. An early version of this patch set had a very
> extensive chunk of Perl code in it that actually understood the page
> layout and, if we adopt something like that, it would probably be
> easier to test a whole bunch of scenarios. The downside is that it was
> a lot of code that basically duplicated a lot of backend logic in
> Perl, and I was (and am) afraid that people will complain about the
> amount of code and/or the difficulty of maintaining it. On the other
> hand, having all that code might allow better testing not only of this
> particular patch but also other scenarios involving corrupted pages,
> so maybe it's wrong to view all that code as a burden that we have to
> carry specifically to test this; or, alternatively, maybe it's worth
> carrying even if we only use it for this. On the third hand, as Mark
> points out, if we get 0002 committed, that will help somewhat with
> test coverage even if we do nothing else.

Much of the test in 0002 could be ported to work without committing the rest of 0002, if the pg_amcheck command line utiilty is not wanted.

>
> Thanks for committing (and adjusting) the patches for the existing
> buildfarm failures. If I understand the buildfarm results correctly,
> hornet is still unhappy even after
> 321633e17b07968e68ca5341429e2c8bbf15c331?

That appears to be a failed test for pg_surgery rather than for amcheck. Or am I reading the log wrong?

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
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