import { Pool, PoolClient, QueryResult, QueryResultRow } from 'pg';
import { TxnOption } from 'oak-domain/lib/types';
import { PostgreSQLConfiguration } from './types/Configuration';
export declare class PostgreSQLConnector {
    pool: Pool;
    configuration: PostgreSQLConfiguration;
    txnDict: Record<string, PoolClient>;
    constructor(configuration: PostgreSQLConfiguration);
    connect(): void;
    disconnect(): Promise<void>;
    startTransaction(option?: TxnOption): Promise<string>;
    /**
     * 映射隔离级别到 PostgreSQL 语法
     */
    private mapIsolationLevel;
    exec(sql: string, txn?: string): Promise<[QueryResultRow[], QueryResult]>;
    commitTransaction(txn: string): Promise<void>;
    rollbackTransaction(txn: string): Promise<void>;
    /**
     * 获取连接池状态
     */
    getPoolStatus(): {
        total: number;
        idle: number;
        waiting: number;
    };
}