From 606536fb4aeb352f775ab9fb1fb1ff2a7ff64c9b Mon Sep 17 00:00:00 2001
From: rafapolo <rafael@extrapolo.com>
Date: Sun, 17 May 2026 11:35:58 +0200
Subject: [PATCH] Fix warm-up blocking: use LIMIT 1 instead of COUNT(*)

COUNT(*) on large tables (CNPJ, RAIS) held the lock for 30s+ each,
blocking all incoming queries during startup. LIMIT 1 warms the S3
file-listing cache in < 1s per table without reading all Parquet footers.
---
 auth.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/auth.py b/auth.py
index aee541b..a2fd39b 100644
--- a/auth.py
+++ b/auth.py
@@ -75,7 +75,7 @@ def _warm_cache():
     for t in hot_tables:
         try:
             with _lock:
-                _con.execute(f"SELECT COUNT(*) FROM basedosdados.{t}")
+                _con.execute(f"FROM basedosdados.{t} LIMIT 1")
         except Exception:
             pass