import { Pool } from 'pg';
import { BaseKeyValueStorage, type BaseKeyValueStorageRow } from './BaseKeyValueStorage';
export interface PostgresKeyValueStorageOptions {
    connectionString: string;
    tableName?: string;
    namespace?: string;
    /**
     * 共享的 pg Pool 实例（避免多个组件创建独立连接池导致死锁）
     * 如果提供，将忽略 connectionString
     */
    pool?: Pool;
}
export declare class PostgresKeyValueStorage<T = unknown> extends BaseKeyValueStorage<T> {
    private readonly pool;
    private readonly quotedTableName;
    private readonly sharedConnectionString?;
    constructor(options: PostgresKeyValueStorageOptions);
    protected closeStorage(): Promise<void>;
    protected hasValue(key: string): Promise<boolean>;
    protected selectValue(key: string): Promise<unknown | undefined>;
    protected upsertValue(key: string, payload: string): Promise<void>;
    protected deleteValue(key: string): Promise<boolean>;
    protected selectEntries(prefix: string): Promise<BaseKeyValueStorageRow[]>;
    private ensureTable;
}