ssb: Faster loads around the profile page. An experiment with caching SQL queries, and make one query just plain faster.

apps/ssb/app.js

@@ -2,6 +2,7 @@ import * as tfrpc from '/tfrpc.js';
 
 let g_database;
 let g_hash;
+let g_sql_cache = {};
 
 tfrpc.register(async function localStorageGet(key) {
 	return app.localStorageGet(key);
@@ -51,14 +52,38 @@ tfrpc.register(async function connect(token) {
 tfrpc.register(async function closeConnection(id) {
 	await ssb.closeConnection(id);
 });
-tfrpc.register(async function query(sql, args) {
+tfrpc.register(async function query(sql, args, options) {
 	let start = new Date();
 	let result = [];
-	await ssb.sqlAsync(sql, args, function callback(row) {
-		result.push(row);
-	});
+	let key = options?.cacheable ? JSON.stringify([sql, args]) : undefined;
+	let entry = key ? g_sql_cache[key] : undefined;
+	const k_ideal_count = 64;
+	if (entry) {
+		result = entry.result;
+	} else {
+		await ssb.sqlAsync(sql, args, function callback(row) {
+			result.push(row);
+		});
+		if (key) {
+			g_sql_cache[key] = {
+				result: result,
+				time: new Date().valueOf(),
+			};
+			if (Object.keys(g_sql_cache).length > k_ideal_count * 2) {
+				let aged = Object.entries(g_sql_cache).map(([k, v]) => [v.time, k]);
+				aged.sort();
+				for (let i = 0; i < aged.length / 2; i++) {
+					delete g_sql_cache[aged[i][1]];
+				}
+			}
+		}
+	}
 	let end = new Date();
-	print((end - start) / 1000, sql.replaceAll(/\s+/g, ' ').trim());
+	print(
+		(end - start) / 1000,
+		entry ? 'from cache' : 'from db',
+		sql.replaceAll(/\s+/g, ' ').trim()
+	);
 	return result;
 });
 tfrpc.register(async function appendMessage(id, message) {