On Mon, Mar 17, 2025 at 07:42:54PM -0700, Elijah Newren wrote: > > +In the incremental MIDX design, we extend this definition to include > > +objects from multiple layers of the MIDX chain. The pseudo-pack order > > +for incremental MIDXs is determined by concatenating the pseudo-pack > > +ordering for each layer of the MIDX chain in order. Formally two objects > > +`o1` and `o2` are compared as follows: > > + > > +1. If `o1` appears in an earlier layer of the MIDX chain than `o2`, then > > + `o1` is considered less than `o2`. > > For sorting order, 'less than' doesn't tell us if you are sorting > smallest to greatest or greatest to smallest. Maybe "less than (so > its order is earlier than) `o2'" ? Oh, good suggestion. I found the alternative a little verbose, but went with "sorts ahead of" instead of "less than". > > + > > +2. Otherwise, if `o1` and `o2` appear in the same MIDX layer, and that > > + MIDX layer has no base, then if one of `pack(o1)` and `pack(o2)` is > > + preferred and the other is not, then the preferred one sorts first. If > > + there is a base layer (i.e. the MIDX layer is not the first layer in > > + the chain), then if `pack(o1)` appears earlier in that MIDX layer's > > + pack order, than `o1` is less than `o2`. Likewise if `pack(o2)` > > s/than/then/ > > > + appears earlier, than the opposite is true. > > s/than/then/ Good catch on both accounts ;-). > > +The structure of a `*.bitmap` file belonging to an incremental MIDX > > +chain is identical to that of a non-incremental MIDX bitmap, or a > > +classic single-pack bitmap. Since objects are added to the end of the > > +incremental MIDX's pseudo-pack order (see: above), it is possible to > > drop the colon? Yep, dropped. > > +extend a bitmap when appending to the end of a MIDX chain. > > + > > +(Note: it is possible likewise to compress a contiguous sequence of MIDX > > +incremental layers, and their `*.bitmap`(s) into a single layer and > > +`*.bitmap`, but this is not yet implemented.) > > "`*.bitmap`(s)" feels slightly awkward and only saves 2 characters. > Maybe just "`*.bitmap` files"? Fair suggestion, sure! > > Future Work > > ----------- > > Should the patch also remove the first item from Future Work, since > this series is implementing it? Hah, that was quite satisfying to do. I moved that to its own commit, though, since this series doesn't implement incremental MIDXs, but bitmap support for them. Incremental MIDXs were "done" as of b9497848df (Merge branch 'tb/incremental-midx-part-1', 2024-08-19). Thanks, Taylor
