Re: heapgettup refactoring

On Thu, 2 Feb 2023 at 10:12, Melanie Plageman <melanieplageman(at)gmail(dot)com> wrote:
> FWIW, I like setting rs_inited in heapgettup_initial_block() better in
> the final refactor, but I agree with you that in this patch on its own
> it is better in the body of heapgettup() and heapgettup_pagemode().

We can reconsider that when we get to that patch. It just felt a bit
ugly to add an InvalidBlockNumber check after calling
table_block_parallelscan_nextpage()

> I believe this else is superfluous since we returned above.

TBH, that's on purpose. I felt that it just looked better that way as
the code all fitted onto my screen. I think if the function was
longer and people had to scroll down to read it, it can often be
better to return and reduce the nesting. This allows you to mentally
not that a certain case is handled above. However, since all these
helper functions seem to fit onto a screen without too much trouble,
it just seems better (to me) if they all follow the format that I
mentioned earlier. I might live to regret that as we often see
get-rid-of-useless-else-clause patches coming up. I'm starting to
wonder if someone's got some alarm that goes off every time one gets
committed, but we'll see. I'd much rather have consistency between the
helper functions than save a few bytes on tab characters. It would be
different if the indentation were shifting things too far right, but
that's not going to happen in a function that all fits onto a screen
at once.

I've attached a version of the next patch in the series. I admit to
making a couple of adjustments. I couldn't bring myself to remove the
snapshot local variable in this commit. We can deal with that when we
come to it in whichever patch that needs to be changed in. The only
other thing I really did was question your use of rs_cindex to store
the last OffsetNumber. I ended up adding a new field which slots into
the padding between a bool and BlockNumber field named rs_coffset for
this purpose. I noticed what Andres wrote [1] earlier in this thread
about that, so thought we should move away from looking at the last
tuple to get this number

I've attached the rebased and updated patch.

David

[1] https://postgr.es/m/20221101010948.hsf33emgnwzvil4a@awork3.anarazel.de