fix: real root cause - ORDER BY id forced a full table scan every batch, use received_at (indexed) instead

server.js

@@ -86,13 +86,13 @@ const stmtSummarizeBatch = DB.prepare(`
   INSERT INTO daily_summary (day, site_id, bot_type, action, country, count)
   SELECT strftime('%Y-%m-%d', received_at, 'unixepoch'), site_id, bot_type, action, country, COUNT(*)
   FROM bots
-  WHERE id IN (SELECT id FROM bots WHERE received_at < ? ORDER BY id LIMIT ?)
+  WHERE id IN (SELECT id FROM bots WHERE received_at < ? ORDER BY received_at LIMIT ?)
   GROUP BY 1, 2, 3, 4, 5
   ON CONFLICT (day, site_id, bot_type, action, country)
   DO UPDATE SET count = count + excluded.count
 `);
 const stmtDeleteBatch = DB.prepare(
-  'DELETE FROM bots WHERE id IN (SELECT id FROM bots WHERE received_at < ? ORDER BY id LIMIT ?)'
+  'DELETE FROM bots WHERE id IN (SELECT id FROM bots WHERE received_at < ? ORDER BY received_at LIMIT ?)'
 );
 
 function pruneOldRowsBatch(cutoff) {