query cache

Author: max-ostapenko

src/controllers/cwvtechController.js

@@ -2,7 +2,10 @@ import { firestoreOld } from '../utils/db.js';
 const firestore = firestoreOld;
 
 import {
-  getLatestDate
+  getLatestDate,
+  generateQueryCacheKey,
+  getCachedQueryResult,
+  setCachedQueryResult
 } from '../utils/controllerHelpers.js';
 
 const TABLE = 'core_web_vitals';
@@ -37,6 +40,24 @@ const listCWVTechData = async (req, res) => {
       startDate = await getLatestDate(firestore, TABLE);
     }
 
+    // Create cache key for this specific query
+    const queryFilters = {
+      geo: params.geo,
+      rank: params.rank,
+      technology: techArray,
+      startDate: startDate,
+      endDate: params.end
+    };
+    const cacheKey = generateQueryCacheKey(TABLE, queryFilters);
+
+    // Check cache first
+    const cachedResult = getCachedQueryResult(cacheKey);
+    if (cachedResult) {
+      res.statusCode = 200;
+      res.end(JSON.stringify(cachedResult));
+      return;
+    }
+
     // Build optimized query
     let query = firestore.collection(TABLE);
 
@@ -49,7 +70,7 @@ const listCWVTechData = async (req, res) => {
       // Use 'in' operator for batch processing (Firestore limit: 30 values)
       query = query.where('technology', 'in', techArray);
     } else {
-      // Parallel queries for >10 technologies (rare case)
+      // Parallel queries for >30 technologies (rare case)
       const queryPromises = techArray.map(async (technology) => {
         let individualQuery = firestore.collection(TABLE)
           .where('geo', '==', params.geo)
@@ -68,6 +89,9 @@ const listCWVTechData = async (req, res) => {
       const results = await Promise.all(queryPromises);
       const data = results.flat();
 
+      // Cache the result
+      setCachedQueryResult(cacheKey, data);
+
       res.statusCode = 200;
       res.end(JSON.stringify(data));
       return;
@@ -84,6 +108,9 @@ const listCWVTechData = async (req, res) => {
       data.push(doc.data());
     });
 
+    // Cache the result
+    setCachedQueryResult(cacheKey, data);
+
     // Direct response without wrapper functions
     res.statusCode = 200;
     res.end(JSON.stringify(data));

src/utils/controllerHelpers.js

@@ -42,6 +42,45 @@ const sendValidationError = (res, errors) => {
 const latestDateCache = new Map();
 const CACHE_TTL = 60 * 60 * 1000; // 1 hour in milliseconds
 
+// Cache for query results to eliminate bimodal performance
+const queryResultCache = new Map();
+const QUERY_CACHE_TTL = 10 * 60 * 1000; // 10 minutes for query results
+
+/**
+ * Generate a cache key for a query
+ * @param {string} collection - Collection name
+ * @param {Object} filters - Query filters
+ * @returns {string} - Cache key
+ */
+const generateQueryCacheKey = (collection, filters) => {
+  return `${collection}:${JSON.stringify(filters)}`;
+};
+
+/**
+ * Get cached query result if available and not expired
+ * @param {string} cacheKey - Cache key
+ * @returns {Array|null} - Cached result or null
+ */
+const getCachedQueryResult = (cacheKey) => {
+  const cached = queryResultCache.get(cacheKey);
+  if (cached && (Date.now() - cached.timestamp) < QUERY_CACHE_TTL) {
+    return cached.data;
+  }
+  return null;
+};
+
+/**
+ * Cache a query result
+ * @param {string} cacheKey - Cache key
+ * @param {Array} data - Query result data
+ */
+const setCachedQueryResult = (cacheKey, data) => {
+  queryResultCache.set(cacheKey, {
+    data: data,
+    timestamp: Date.now()
+  });
+};
+
 /**
  * Get the latest date from a collection with caching
  * @param {Object} firestore - Firestore instance
@@ -209,5 +248,8 @@ export {
   preprocessParams,
   applyArrayFilter,
   selectFields,
-  handleControllerError
+  handleControllerError,
+  generateQueryCacheKey,
+  getCachedQueryResult,
+  setCachedQueryResult
 };

src/utils/helpers.js

@@ -45,4 +45,4 @@ const createErrorResponse = (errors) => {
   };
 };
 
-export { convertToArray, convertToHashes, createSuccessResponse, createErrorResponse };
+export { convertToArray, createSuccessResponse, createErrorResponse };