Tz World version 2.1.0

Tz_World v2.1.0

Enhancements

THe primary focus in this release is peak memory used during the mix tz_world.update process. With the changes in this release, peak memory has been reduced from about 920Mb to about 70Mb.

• On-disk data format upgraded; existing installations must run mix tz_world.update once after upgrading.

• The :jason dependency has been removed in favour of the built-in :json module (with :json_polyfill on OTP < 27)."

Tz_World v2.0.0

Enhancements

• Adds TzWorld.Backend.SpatialIndex, a new backend that resolves timezones using a pure-Elixir R-tree (Sort-Tile-Recursive packed) held in :persistent_term. Lookups bypass the GenServer mailbox and read directly from :persistent_term, eliminating the linear bounding-box scan used by the previous backends.

• TzWorld.Backend.SpatialIndex is now the default backend, and is the first entry in the default backend precedence list. Existing applications that do not pin :default_backend will pick it up automatically.

• Benchmarked against the previous backends across a categorised fixture set (dense regions, sparse/large zones, small/thin zones, ocean points with no match, points adjacent to the international date line):

  Input category	Speedup vs. the next-fastest existing backend
  ocean (no-match)	18.2×
  sparse_or_large	1.64×
  dense (cities)	1.43×
  random uniform	1.42×
  small_or_thin	1.08×

  The largest wins are on no-match queries: previously, points in the open ocean caused a full scan of every shape's bounding box; the R-tree exits at the root.

• Adds TzWorld.SpatialIndex, a small standalone R-tree implementation (build + stab) used by the new backend.

• Adds TzWorld.TimezoneFixtures, a categorised set of coordinate fixtures used by both the test suite and the benchmark.

Breaking Changes

• Removes TzWorld.Backend.Memory. It is strictly dominated by TzWorld.Backend.SpatialIndex on every measured workload (same memory profile, faster lookups, no GenServer round-trip).

• Removes TzWorld.Backend.Ets. Without an in-memory bbox index, every lookup on a no-match point performed a full ETS scan via match-spec — orders of magnitude slower than the index-cache variant or the new SpatialIndex backend. TzWorld.Backend.EtsWithIndexCache remains for users who want ETS-backed shape storage.

• Removes TzWorld.Backend.Dets. Same reasoning as Backend.Ets. TzWorld.Backend.DetsWithIndexCache remains for users who want disk-backed shape storage.