Use NullPool and keepalive settings for PostgreSQL

Author: rprabhat

backend/app/database.py

@@ -1,38 +1,36 @@
 from sqlalchemy import create_engine
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import sessionmaker
+from sqlalchemy.pool import NullPool
 import os
 import sys
+import psycopg2
 
-# Force redeploy - testing SSL fix
 DATABASE_URL = os.environ.get("DATABASE_URL")
 sys.stderr.write(
-    f"[DB DEBUG] DATABASE_URL: {DATABASE_URL[:100] if DATABASE_URL else 'None'}\n"
+    f"[DB DEBUG] DATABASE_URL: {DATABASE_URL[:80] if DATABASE_URL else 'None'}\n"
 )
 sys.stderr.write(f"[DB DEBUG] DATA_DIR: {os.environ.get('DATA_DIR', 'Not set')}\n")
-sys.stderr.write(f"[DB DEBUG] Python version: {sys.version}\n")
 
-# INTENTIONAL ERROR TO TEST IF CODE IS BEING USED
 RAILWAY_TEST_VARIABLE = "THIS_SHOULD_APPEAR_IN_LOGS_IF_CODE_IS_LOADED"
 
 if DATABASE_URL:
     if DATABASE_URL.startswith("postgresql://"):
-        sys.stderr.write(
-            f"[DB DEBUG] Using DATABASE_URL: {DATABASE_URL[:80]}...\n"
-        )
+        sys.stderr.write(f"[DB DEBUG] Using PostgreSQL with NullPool\n")
         engine = create_engine(
             DATABASE_URL,
-            pool_pre_ping=True,
-            pool_recycle=300,
+            poolclass=NullPool,
             connect_args={
                 "connect_timeout": 10,
-                "sslmode": "require"
-            }
+                "sslmode": "require",
+                "keepalives": 1,
+                "keepalives_idle": 30,
+                "keepalives_interval": 10,
+                "keepalives_count": 5,
+            },
         )
     else:
         engine = create_engine(DATABASE_URL)
-else:
-        engine = create_engine(DATABASE_URL)
 else:
     BASE_DIR = os.path.dirname(os.path.abspath(__file__))
     DATA_DIR = os.environ.get("DATA_DIR", "/tmp")