Re: [PATCH] Clarify the comments about varlena header encoding

Hi John,

Many thanks for the feedback!

> Or put the now-standard 0b in front.

Good idea.

> I think the problem is ambiguity about what a "toast pointer" is. This comment:
>
> * struct varatt_external is a traditional "TOAST pointer", that is, the

Right. The comment for varatt_external says that it IS a TOAST
pointer. However the comments for varlena headers bit layout
implicitly include it into a TOAST pointer, which contradicts the
previous comments. I suggest we fix this ambiguity by explicitly
enumerating the type tag in the comments for varlena headers.

> The patch added xxx's for the type tag in a comment about
> the header. This is more misleading than what is there now.

OK, here is another attempt. Changes compared to v1:

* "xxx xxx xxx" were removed, according to the feedback
* 0b prefix was added in order to make sure the reader will not
misread this as a hex values
* The clarification about the type tag was added
* The references to "first case", "second case", etc were removed

Hopefully it's better now.

--
Best regards,
Aleksander Alekseev