Re: Reducing the chunk header sizes on all memory context types

On Tue, 20 Sept 2022 at 13:23, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> David Rowley <dgrowleyml@gmail.com> writes:
> > Aside from that, I don't have any ideas on how to get rid of the
> > possible additional datumCopy() from non-Var arguments to these window
> > functions.  Should we just suffer it? It's quite likely that most
> > arguments to these functions are plain Vars anyway.
>
> No, we shouldn't.  I'm pretty sure that we have various window
> functions that are deliberately designed to take advantage of the
> no-copy behavior, and that they have taken a significant speed
> hit from your having disabled that optimization.  I don't say
> that this is enough to justify reverting the chunk header changes
> altogether ... but I'm completely not satisfied with the current
> situation in HEAD.

Maybe you've forgotten that MemoryContextContains() is broken in the
back branches or just don't think it is broken?

David