On 2017-04-08 17:20:28 -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > On Sat, Apr 8, 2017 at 3:57 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> This makes me wonder whether we were being penny-wise and pound-foolish
> >> by not making Bitmapsets be a kind of Node, so that there could be IsA
> >> assertions in the bitmapset.c routines, as there are for Lists.
>
> > I think it's pretty dubious to change this, honestly. Just because it
> > would have caught this one bug doesn't make it an especially valuable
> > thing in general. Bytes are still not free.
>
> Yeah, true. OTOH I recall Andres lobbying to change the bitmap word
> size to 64 bits on 64-bit hardware, and it *would* be free in that case
> due to alignment padding.
Hah, yes, I did. A loong time ago ;) I still think it's a good idea, and
probably has become more useful with just about anyone using 64bits
these days. Also interesting for tidbitmap, which reuses bitmapset's
bitmapword.
> We could also consider installing the nodetag only in Assert-enabled
> builds, although that approach would prevent us from applying followon
> simplifications such as not having to treat bitmapset fields specially
> in copyfuncs.c and like places.
Yea, don't like this much.
- Andres
