order by downloaded time to improve ebs read performance

pipeline/05_bundle_gen/main.go

@@ -135,6 +135,7 @@ func main() {
 	// Stage 1: DB fetcher — continuously fetches pages into hostCh
 	go func() {
 		defer close(hostCh)
+		var lastDownloaded *time.Time
 		var lastID int64
 		pageSize := 50000
 		fetched := 0
@@ -150,14 +151,16 @@ func main() {
 				}
 			}
 			fetchStart := time.Now()
-			hosts, err := fetchHostsPage(ctx, pool, lastID, limit)
+			hosts, err := fetchHostsPage(ctx, pool, lastDownloaded, lastID, limit)
 			if err != nil {
 				log.Fatalf("Failed to fetch hosts: %v", err)
 			}
 			if len(hosts) == 0 {
 				break
 			}
-			lastID = hosts[len(hosts)-1].ID
+			last := hosts[len(hosts)-1]
+			lastDownloaded = last.IconDownloadedAt
+			lastID = last.ID
 			fmt.Printf("[fetcher] %d hosts in %dms (hostCh: %d/%d)\n",
 				len(hosts), time.Since(fetchStart).Milliseconds(), len(hostCh), cap(hostCh))
 			for _, h := range hosts {