import type { PostgreSQL } from "@cocalc/database/postgres/types";
declare function _number_of_clients(): number;
export { _number_of_clients as number_of_clients };
declare function _database_is_working(): boolean;
export { _database_is_working as database_is_working };
interface Opts {
    database: PostgreSQL;
    clients: any;
    host: string;
    port: number;
    interval_s: number;
    cb?: Function;
}
export declare function start(opts: Opts): void;