DEFAULT_FRONTIER_WINDOW

How many contiguous runs of archived insert dots are remembered by default.

Counted in runs, not operations: an author whose dots arrive densely costs one entry however long its log is, and one more for each hole that has not filled. Size it in runs, not in peers. Those are the same number only while every peer's dots arrive densely, and what breaks that is neither rare nor second-order:

Rga.compact collects a scattered set of tombstoned, causally-stable ids — not a prefix — and purges each one's operations from the log. Rga.dropWindow folds only the dropping replica's own contiguous seqs into its floor, recording every foreign author's dropped dots as an explicit compaction record instead. So a decorator opened against a mesh that has already been running meets one author's live seqs with holes scattered through them, and every hole is a run: a single author can exhaust this on its own, with no fleet at all. An archive attached to an established mesh is the case to size against. One present from the mesh's first operation never sees those holes, because it archived the operations before anything collected them.

4,096 is comfortable for the ordinary shape, and costs a few hundred kilobytes when the runs are concentrated in a handful of authors. It costs nearer a megabyte when they are 4,096 distinct authors, each bringing a map entry, a ReplicaId and a list of its own — worth knowing before raising it an order of magnitude.

Past it the shortest run is evicted and the inserts it covered are archived a second time, which costs bytes and never correctness.