From 2f41c38cc420a4be24ab7cf78b391f7c8079f140 Mon Sep 17 00:00:00 2001
From: Andras Schmelczer <andras@schmelczer.dev>
Date: Mon, 26 Jan 2026 20:42:52 +0000
Subject: [PATCH] Fix loading times

---
 frontend/src/components/Map.tsx |  3 ++-
 frontend/src/types.ts           |  1 -
 server/main.py                  | 12 ++++++++++-
 server/routes/hexagons.py       | 36 +++++++++++++++++++--------------
 4 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/frontend/src/components/Map.tsx b/frontend/src/components/Map.tsx
index 5628b96..5cd173b 100644
--- a/frontend/src/components/Map.tsx
+++ b/frontend/src/components/Map.tsx
@@ -164,7 +164,8 @@ export default function Map({ data, onViewChange }: MapProps) {
         getFillColor: (d) => priceToColor(d.avg_price),
         extruded: false,
         pickable: true,
-        opacity: 0.7,
+        opacity: 0.5,
+        highPrecision: true,
       }),
     ],
     [data]
diff --git a/frontend/src/types.ts b/frontend/src/types.ts
index 561d293..ecfe433 100644
--- a/frontend/src/types.ts
+++ b/frontend/src/types.ts
@@ -37,5 +37,4 @@ export interface ViewChangeParams {
 
 export interface ApiResponse {
   features: HexagonData[];
-  truncated: boolean;
 }
diff --git a/server/main.py b/server/main.py
index 14cf941..511016c 100644
--- a/server/main.py
+++ b/server/main.py
@@ -1,3 +1,4 @@
+from contextlib import asynccontextmanager
 from pathlib import Path
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
@@ -5,7 +6,16 @@ from fastapi.staticfiles import StaticFiles
 
 from server.routes import hexagons
 
-app = FastAPI(title="Property Map API")
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Startup: preload all parquet files
+    hexagons.preload_dataframes()
+    yield
+    # Shutdown: nothing to clean up
+
+
+app = FastAPI(title="Property Map API", lifespan=lifespan)
 
 app.add_middleware(
     CORSMiddleware,
diff --git a/server/routes/hexagons.py b/server/routes/hexagons.py
index 40835e9..b4cc24f 100644
--- a/server/routes/hexagons.py
+++ b/server/routes/hexagons.py
@@ -1,8 +1,11 @@
+import math
 from functools import lru_cache
 from fastapi import APIRouter, Query, HTTPException
 import polars as pl
 import h3
 
+from tqdm import tqdm
+
 from server.config import (
     AGGREGATES_DIR,
     VALID_RESOLUTIONS,
@@ -19,6 +22,12 @@ router = APIRouter()
 _df_cache: dict[int, pl.DataFrame] = {}
 
 
+def preload_dataframes() -> None:
+    """Load all resolution dataframes into cache on startup."""
+    for resolution in tqdm(VALID_RESOLUTIONS, desc="Loading parquet files"):
+        get_cached_df(resolution)
+
+
 def get_cached_df(resolution: int) -> pl.DataFrame | None:
     """Get cached dataframe for resolution, loading from disk if needed."""
     if resolution not in _df_cache:
@@ -48,8 +57,8 @@ def query_hexagons_cached(
     min_price: int,
     max_price: int,
     bounds_tuple: tuple[float, float, float, float],
-) -> tuple[list[dict], bool]:
-    """Cached query - returns (features, truncated)."""
+) -> list[dict]:
+    """Cached query - returns features list."""
     south, west, north, east = bounds_tuple
 
     df = get_cached_df(resolution)
@@ -86,12 +95,6 @@ def query_hexagons_cached(
         (pl.col("avg_price") >= min_price) & (pl.col("avg_price") <= max_price)
     )
 
-    # Limit results
-    MAX_HEXAGONS = 50000
-    truncated = len(df) >= MAX_HEXAGONS
-    if truncated:
-        df = df.limit(MAX_HEXAGONS)
-
     # Build response efficiently using Polars
     df = df.select(
         [
@@ -104,7 +107,7 @@ def query_hexagons_cached(
         ]
     )
 
-    return df.to_dicts(), truncated
+    return df.to_dicts()
 
 
 @router.get("/hexagons")
@@ -136,15 +139,18 @@ async def get_hexagons(
         )
 
     # Round bounds to reduce cache misses (0.01 degree ≈ 1km precision)
+    # Always expand bounds (floor for min, ceil for max) to prevent hexagons
+    # popping in when crossing rounding boundaries
+    precision = 0.01
     bounds_tuple = (
-        round(south, 2),
-        round(west, 2),
-        round(north, 2),
-        round(east, 2),
+        math.floor(south / precision) * precision,
+        math.floor(west / precision) * precision,
+        math.ceil(north / precision) * precision,
+        math.ceil(east / precision) * precision,
     )
 
     # Convert prices to int for cache key hashability
-    features, truncated = query_hexagons_cached(
+    features = query_hexagons_cached(
         resolution,
         min_year,
         max_year,
@@ -153,4 +159,4 @@ async def get_hexagons(
         bounds_tuple,
     )
 
-    return {"features": features, "truncated": truncated}
+    return {"features": features}