Re: HOT chain validation in verify_heapam()

On Wed, Mar 22, 2023 at 3:27 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> My animal mamba doesn't like this one bit.
>
> I suspect the reason is that it's big-endian (PPC) and the endianness
> hacking in the test is simply wrong:
>
>         syswrite($file,
>                  pack("L", $ENDIANNESS eq 'little' ? 0x00010019 : 0x19000100))
>             or BAIL_OUT("syswrite failed: $!");
>
> pack's L code should already be performing an endianness swap, so why
> are we doing another one in the argument?

(Apologies for having missed responding to this yesterday afternoon.)

Hmph. I didn't think very hard about that code and just assumed
Himanshu had tested it. I don't have convenient access to a Big-endian
test machine myself. Are you able to check whether using 0x00010019
unconditionally works?

I think part of the reason that I thought this looked OK was because
there are other places in this test case that do stuff differently
based on endian-ness, but now that you mention it, I realize that
stuff has to do with the varlena representation, which is
endian-dependent in a way that the ItemIdData representation is not.

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