store: Fix: batch PitchingCardRatings lookup in pitcher sort (paper-dynasty-database #19)

graph/fixes/fix-batch-pitchingcardratings-lookup-in-pitcher-sort-paper-d-e014f5.md

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+---
+id: e014f59b-60ff-4602-91bc-076b3a73f0e8
+type: fix
+title: "Fix: batch PitchingCardRatings lookup in pitcher sort (paper-dynasty-database #19)"
+tags: [paper-dynasty-database, python, peewee, pandas, performance, fix, n+1-queries]
+importance: 0.65
+confidence: 0.8
+created: "2026-03-03T23:04:16.395675+00:00"
+updated: "2026-03-03T23:04:16.395675+00:00"
+---
+
+## Problem
+`sort_pitchers()` and `sort_starters()` in `app/routers_v2/teams.py` called `PitchingCardRatings.get_or_none()` twice per row inside a `DataFrame.apply()` — once for vs_hand="L" and once for "R". With 30 pitchers this was 60 queries.
+
+## Solution
+Before the `apply`, batch-fetch all ratings for all card IDs in one query and build a `(pitchingcard_id, vs_hand) → rating` dict. The closure does O(1) dict lookups.
+
+```python
+card_ids = pitcher_df["id"].tolist()
+ratings_map = {
+    (r.pitchingcard_id, r.vs_hand): r
+    for r in PitchingCardRatings.select().where(
+        (PitchingCardRatings.pitchingcard_id << card_ids)
+        & (PitchingCardRatings.vs_hand << ["L", "R"])
+    )
+}
+
+def get_total_ops(df_data):
+    vlval = ratings_map.get((df_data["id"], "L"))
+    vrval = ratings_map.get((df_data["id"], "R"))
+    ...
+```
+
+## Files Changed
+- `app/routers_v2/teams.py` — both `sort_pitchers` and nested `sort_starters`
+
+## Pattern
+General pattern for Peewee + pandas: never do model lookups inside `DataFrame.apply`. Batch fetch with `model << id_list`, build a dict, use dict lookup in the closure.