Optimise db query. Add more error detail.

backend/app/server.js

@@ -66,18 +66,27 @@ app.get('/api/line-of-sight', async (req, res) => {
       pathPoints.push(calculateDestination(startLat, startLon, bearing, dist));
     }
 
-    // Batch water check: a point is "over water" if no city is within 500 km
-    const waterChecks = await Promise.all(pathPoints.map(async (p) => {
-      const checkQuery = `
-        SELECT EXISTS (
-          SELECT 1 FROM cities
-          WHERE ST_DWithin(geom, ST_SetSRID(ST_MakePoint($1, $2), 4326)::geography, 500000)
-          LIMIT 1
-        ) as has_land;
-      `;
-      const r = await pool.query(checkQuery, [p.lon, p.lat]);
-      return !r.rows[0].has_land;
-    }));
+    // Bulk land check: use a single query for all points to avoid connection pool exhaustion
+    const waterStart = Date.now();
+    const waterCheckQuery = `
+      WITH points AS (
+        SELECT i, ST_SetSRID(ST_MakePoint(val[1], val[2]), 4326)::geography as p_geom
+        FROM unnest($1::float8[][]) WITH ORDINALITY AS t(val, i)
+      )
+      SELECT i, EXISTS (
+        SELECT 1 FROM cities 
+        WHERE ST_DWithin(geom, p_geom, 500000)
+        LIMIT 1
+      ) as has_land
+      FROM points
+      ORDER BY i;
+    `;
+    
+    const pointsArray = pathPoints.map(p => [p.lon, p.lat]);
+    const waterResults = await pool.query(waterCheckQuery, [pointsArray]);
+    const waterChecks = waterResults.rows.map(r => !r.has_land);
+    
+    console.log(`Bulk water check completed in ${Date.now() - waterStart}ms for ${pathPoints.length} points.`);
 
     const pathPointsWithWater = pathPoints.map((p, i) => ({
       ...p,
@@ -116,10 +125,13 @@ app.get('/api/line-of-sight', async (req, res) => {
       ORDER BY pos_on_line ASC;
     `;
 
+    const startTime = Date.now();
     const result = await pool.query(query, [lineWKT, toleranceKm, startLon, startLat]);
+    const queryTime = Date.now() - startTime;
+    console.log(`Query completed in ${queryTime}ms. Found ${result.rows.length} candidates.`);
 
-    // Greedy dynamic deduplication: sort by population desc, accept a city only if
-    // it satisfies a distance threshold that depends on its importance (population).
+    const startDedupe = Date.now();
+    // Greedy dynamic deduplication...
     const byPopulation = [...result.rows].sort((a, b) => (b.population || 0) - (a.population || 0));
     const accepted = [];
     for (const city of byPopulation) {
@@ -127,21 +139,14 @@ app.get('/api/line-of-sight', async (req, res) => {
       const tooClose = accepted.some(s => {
         const dist = haversineKm(s.lat, s.lon, city.lat, city.lon);
         const sPop = s.population || 0;
-
-        // Major hubs (>1M) can be closer (30km) to each other (e.g., Tokyo/Yokohama)
         if (cityPop > 1000000 && sPop > 1000000) return dist < 30;
-        
-        // Large cities (>100k) need at least 50km space
         if (cityPop > 100000 || sPop > 100000) return dist < 50;
-        
-        // Smaller towns and villages need 80km space from any other accepted place
-        // to prevent clutter in high-density regions (like Europe/East Coast).
-        // Isolated towns (Alaska/Outback) will still show up as there's nothing else near them.
         return dist < 80;
       });
       if (!tooClose) accepted.push(city);
     }
     accepted.sort((a, b) => a.pos_on_line - b.pos_on_line);
+    console.log(`Deduplication completed in ${Date.now() - startDedupe}ms. Final count: ${accepted.length}`);
 
     res.json({
       success: true,
@@ -159,6 +164,7 @@ app.get('/api/line-of-sight', async (req, res) => {
         line_coordinates: pathPointsWithWater
       }
     });
+    console.log(`Request fully processed in ${Date.now() - startTime}ms`);
   } catch (err) {
     console.error('Database query error:', err);
     res.status(500).json({ success: false, error: 'Database query failed' });

frontend/src/App.jsx

@@ -751,7 +751,8 @@ const APP = () => {
       renderLineOnMap(response.data.data);
     } catch (error) {
       console.error('Error fetching line of sight:', error);
-      setApiError('Failed to fetch route. Please try again.');
+      const msg = error.response?.data?.error || error.message || 'Failed to fetch route.';
+      setApiError(`Error: ${msg}`);
     } finally {
       setLoading(false);
       // Reset flight progress for a new line calculation

frontend/src/services/api.js

@@ -4,7 +4,7 @@ const API_BASE_URL = import.meta.env.VITE_API_URL || '/api';
 
 const api = axios.create({
   baseURL: API_BASE_URL,
-  timeout: 10000,
+  timeout: 30000,
   headers: {
     'Content-Type': 'application/json'
   }