Re: CompactCheckpointerRequestQueue versus pad bytes

On Mon, Jul 16, 2012 at 11:57 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I wrote:
>> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>> So I'm having a hard time understanding under what imaginable set of
>>> circumstances this might break.
>
>> Padding inside RelFileNodeBackend would break it, because
>> ForwardFsyncRequest copies the rnode as a struct. So that's why I'm
>> asking whether we want to establish an explicit requirement that that
>> struct not contain any padding.
>
> BTW, I'd be a lot happier about assuming that bare RelFileNode contains
> no padding, because that's at least got all the fields the same type.
> So that brings us back to the question of why this code is supporting
> fsync requests for local relations in the first place. Couldn't we have
> it ignore those, and then only ship RelFileNode to the checkpointer?

That's an awfully good point. I think that was just sloppy coding on
my part (cf commit debcec7dc31a992703911a9953e299c8d730c778). +1 for
changing it as you suggest.

--
Robert Haas
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