On Fri, Dec 8, 2023 at 9:44 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Fri, Dec 8, 2023 at 7:46 PM John Naylor <johncnaylo...@gmail.com> wrote: > > > > On Fri, Dec 8, 2023 at 3:06 PM Masahiko Sawada <sawada.m...@gmail.com> > > wrote: > > > > > > BTW Given that the actual value size can be calculated only by the > > > caller, how does the tree know if the value is embedded or not? It's > > > probably related to how to store combined pointer/value slots. > > > > Right, this is future work. At first, variable-length types will have > > to be single-value leaves. In fact, the idea for storing up to 3 > > offsets in the bitmap header could be done this way -- it would just > > be a (small) single-value leaf. > > Agreed. > > > > > (Reminder: Currently, fixed-length values are compile-time embeddable > > if the platform pointer size is big enough.) > > > > > If leaf > > > nodes have a bitmap array that indicates the corresponding slot is an > > > embedded value or a pointer to a value, it would be easy. > > > > That's the most general way to do it. We could do it much more easily > > with a pointer tag, although for the above idea it may require some > > endian-aware coding. Both were mentioned in the paper, I recall. > > True. Probably we can use the combined pointer/value slots approach > only if the tree is able to use the pointer tagging. That is, if the > caller allows the tree to use one bit of the value. > > I'm going to update the patch based on the recent discussion (RT_SET() > and variable-length values) etc., and post the patch set early next > week.
I've attached the updated patch set. From the previous patch set, I've merged patches 0007 to 0010. The other changes such as adding RT_GET() still are unmerged for now, for discussion. Probably we can make them as follow-up patches as we discussed. 0011 to 0015 patches are new changes for v44 patch set, which removes RT_SEARCH() and RT_SET() and support variable-length values. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
v44-ART.tar.gz
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