Allow max_connections to be configured in postgres

config.ini.example

@@ -20,3 +20,4 @@ user = your_username
 password = your_password
 database = your_database
 workspace = default  # 可选,默认为default
+max_connections = 12

lightrag/kg/postgres_impl.py

@@ -54,7 +54,7 @@ class PostgreSQLDB:
         self.password = config.get("password", None)
         self.database = config.get("database", "postgres")
         self.workspace = config.get("workspace", "default")
-        self.max = 12
+        self.max = config.get("max_connections", 12)
         self.increment = 1
         self.pool: Pool | None = None
 
@@ -250,6 +250,10 @@ class ClientManager:
                 "POSTGRES_WORKSPACE",
                 config.get("postgres", "workspace", fallback="default"),
             ),
+            "max_connections": os.environ.get(
+                "POSTGRES_MAX_CONNECTIONS",
+                config.get("postgres", "max_connections", fallback=12),
+            ),
         }
 
     @classmethod