Queue executable speed and peer-to-peer sharing plans with tested patches and harnesses

plans/patches/010-retention-eviction.diff

@@ -0,0 +1,44 @@
+--- a/server/media-cache.js
++++ b/server/media-cache.js
+@@ -226,7 +226,10 @@
+     let { bytes } = await db.mediaStats();
+     if (bytes + est > maxBytes) {
+       const cutoff = now() - EVICT_PROTECT_MS;
+-      for (const r of await db.listMediaLru()) {
++      // Retention order (plan 010) when the server provides it: copies that
++      // are neither top nor recent go first. Otherwise plain LRU.
++      const order = db.listMediaEvictionOrder ? await db.listMediaEvictionOrder() : await db.listMediaLru();
++      for (const r of order) {
+         if (bytes + est <= maxBytes) break;
+         if (r.video_id === id || r.last_access > cutoff || jobs.has(r.video_id) || optActive === r.video_id) continue;
+         await evict(r.video_id, 'budget');
+--- a/server/media-cache.test.js
++++ b/server/media-cache.test.js
+@@ -240,6 +240,27 @@
+     expect(await cache.getReady('lruAAAAAAA3')).not.toBeNull();
+   });
+ 
++  test('eviction follows listMediaEvictionOrder when the db provides it', async () => {
++    await clearDb();
++    const size = readFileSync(fx('good.mp4')).length;
++    const db = {
++      getMedia: dbmod.getMedia, upsertMedia: dbmod.upsertMedia, deleteMedia: dbmod.deleteMedia,
++      listMedia: dbmod.listMedia, listMediaLru: dbmod.listMediaLru, touchMedia: dbmod.touchMedia,
++      mediaStats: dbmod.mediaStats,
++      // Retention says the MORE recently played #2 is the one to drop (e.g. no views).
++      listMediaEvictionOrder: async () => (await dbmod.listMediaLru()).reverse(),
++    };
++    const { cache } = makeCache({ db, maxBytes: size * 2 + 60 * 250 * 1024 + 50_000, duration: 10 });
++    await cache.init();
++    await cache.ensureCached('retAAAAAAA1', { priority: HIGH });
++    await cache.ensureCached('retAAAAAAA2', { priority: HIGH });
++    await dbmod.upsertMedia('retAAAAAAA1', { last_access: 1000 });
++    await dbmod.upsertMedia('retAAAAAAA2', { last_access: 2000 });
++    await cache.ensureCached('retAAAAAAA3', { priority: HIGH });
++    expect(await dbmod.getMedia('retAAAAAAA2')).toBeNull();
++    expect(await dbmod.getMedia('retAAAAAAA1')).not.toBeNull();
++  });
++
+   test('free-disk guard skips caching', async () => {
+     await clearDb();
+     const { cache, calls } = makeCache({ freeBytes: () => 1024 ** 3, minFreeBytes: 5 * 1024 ** 3 });