# Performance notes

## Player cache (`ShaguTweaks_player_cache`)

The account-wide player cache feeds Social Colors, Chat Levels and the
nameplate/chat class colors. It is read at every login and `/reload` and
written at every logout, so its size is a direct load-time and memory cost.
Earlier versions let it grow without limit; one account reached 4.1 MB.

`libs/libunitscan.lua` now owns expiry and runs it once per session, at the
first loading screen:

| Entry | Kept for |
|---|---|
| Player whose class is known | 180 days after last sighting |
| Player whose class was never learned | 90 days after last sighting |
| Whole cache | at most 10,000 players; the oldest sightings go first |

- Every sighting refreshes the age: mouseover, target, nameplate, party,
  raid, guild roster, friend list, `/who` and chat.
- Guild members and friends are refreshed by their roster events every
  session, so they do not expire while they stay in the guild or friend list.
- Entries saved before this change have no age. They are dated from the
  cache's existing grace start (`players_cleanup`), as the old Social Colors
  cleanup did. The first login after the update can remove many entries.
- A player's GUID is saved only while the class is unknown. Such entries are
  resolved later with `GetPlayerInfoByGUID` when the engine knows the GUID.

The separate 180-day cleanup in Social Colors is removed. It ran only every
180 days and only while that module was enabled.

## Event handling

- Chat: a speaker whose class is known and who spoke within the hour needs
  no GUID lookup or write.
- Guild roster: a full rescan runs at most once a minute unless the member
  count changed. Many addons request the roster every few seconds.
- Mouseover, target, nameplate and group sightings skip `UnitGUID` when
  `UnitClass` already gave the class.
- A name missing from the cache queries ClassicAPI's player cache once
  instead of twice.

## Range Color

The module shared Blizzard's `rangeTimer` and tested it against 0.2 seconds.
Once the timer had reset, that test was always true, so the full range check
ran on every frame for every ranged action button. It now keeps its own
0.2-second timer. Blizzard's own range check runs again, so the hotkey text
turns red out of range, as in the default UI.

## Map and portrait checks

- WorldMap Class Colors updates its icons ten times a second, and only while
  the world map or battlefield minimap is open. It used to run a check on
  every frame with both maps closed.
- Class Portraits checks the target of target five times a second, plus at
  once when the stock frame reports a new name. It used to call `UnitGUID`
  on every frame.

## Not changed

- Enlarged Minimap still checks the buff anchors every frame while the
  default buff frame is shown. The stock `BuffFrame_Enchant_OnUpdate` moves
  the buff frame back on every frame, so a less frequent check would let the
  buffs jump under the minimap. It writes only when an anchor has actually
  moved. The check is a child of `BuffFrame`, so it stops when a buff addon
  such as VCB hides the default buffs (the stock re-anchoring stops then too).

- Health Numbers and Big Health use one-shot deferred updates only.
- Both castbars update only while visible; Energy Tick hides at full mana
  out of combat.
- Free Slot Count counts slots once per `BAG_UPDATE_DELAYED`. Disable it if a
  bag addon already shows the count.

Nothing here has been measured in game yet. To compare before and after, see
[Measuring performance](CLASSICAPI_UPDATES.md#measuring-performance).