import { PubSubEngine } from "graphql-subscriptions";
import { Client, ClientConfig } from "pg";
interface PostgresPubSubOptions extends ClientConfig {
    commonMessageHandler?: (message: any) => any;
    client?: Client;
    maxListeners?: number;
    usePayloadTable?: boolean;
}
declare class PostgresPubSub extends PubSubEngine {
    private client;
    private ee;
    private subscriptions;
    private subIdCounter;
    private commonMessageHandler;
    private usePayloadTable;
    constructor(options?: PostgresPubSubOptions);
    private ensureTableExists;
    publish(triggerName: string, payload: any): Promise<void>;
    subscribe(triggerName: string, onMessage: (message: any) => void): Promise<number>;
    unsubscribe(subId: number): Promise<void>;
    asyncIterator<T>(triggers: string | string[]): AsyncIterator<T>;
}
export { PostgresPubSub, PostgresPubSubOptions };