diff --git a/backend/src/db/main.py b/backend/src/db/main.py
index 4f0719af..dcbf0c32 100644
--- a/backend/src/db/main.py
+++ b/backend/src/db/main.py
@@ -3,7 +3,12 @@
 
 from src.constants import CONN_STR
 
-engine = create_engine(CONN_STR)
+# pool_pre_ping: a pooled connection idle across the hourly-cron gap goes stale
+# (Cloud SQL / db-f1-micro / the Cloud SQL proxy reap idle connections), and the
+# next query raises "server closed the connection unexpectedly", 500ing the ETL
+# trigger and stalling ingestion. pre_ping reconnects transparently; recycle
+# drops connections older than 30 min proactively.
+engine = create_engine(CONN_STR, pool_pre_ping=True, pool_recycle=1800)
 
 Session = sessionmaker(bind=engine)