import { QueryHookPlugin, ConnectionPoolContext } from '../index';
/**
 * Connection leak details
 */
export interface ConnectionLeak {
    connectionId: string;
    age: number;
    stackTrace?: string;
    queries: number;
}
/**
 * Options for ConnectionLeakDetectorPlugin
 */
export interface ConnectionLeakDetectorOptions {
    /**
     * Maximum connection age in milliseconds (default: 30000ms / 30 seconds)
     * Connections held longer than this are considered potential leaks
     */
    maxConnectionAge?: number;
    /**
     * Warn threshold as percentage of pool capacity (default: 0.8 / 80%)
     * Warns when pool usage exceeds this percentage
     */
    warnThreshold?: number;
    /**
     * Capture stack trace on connection acquire (default: true)
     * Helps identify where leaks originate
     */
    captureStackTrace?: boolean;
    /**
     * Callback when connection leak is detected (optional)
     *
     * @param leak - Connection leak details
     */
    onLeak?: (leak: ConnectionLeak) => void;
    /**
     * Callback when pool capacity warning is triggered (optional)
     *
     * @param context - Connection pool context
     */
    onPoolWarning?: (context: ConnectionPoolContext) => void;
    /**
     * Enable console logging for this plugin (default: false)
     */
    enableLogging?: boolean;
}
/**
 * Plugin for detecting database connection leaks
 * Prevents connection pool exhaustion and app crashes
 *
 * 💧 CRITICAL: Connection leaks cause "no available connections" errors
 *
 * **The Problem:**
 * ```typescript
 * const queryRunner = dataSource.createQueryRunner();
 * await queryRunner.connect();
 * await queryRunner.query('SELECT ...');
 * // FORGOT to call queryRunner.release() !!!
 * // Connection is leaked - never returned to pool
 * ```
 *
 * **Common Causes:**
 * 1. Forgot to call queryRunner.release()
 * 2. Exception thrown before release()
 * 3. Early return in function
 * 4. Async/await mistakes
 *
 * **What it detects:**
 * - Connections held too long
 * - Pool capacity warnings
 * - Stack traces of where connections were acquired
 *
 * @example
 * ```typescript
 * import { ConnectionLeakDetectorPlugin } from 'typeorm-query-hooks/plugins/connection-leak-detector';
 *
 * registerPlugin(ConnectionLeakDetectorPlugin({
 *   maxConnectionAge: 30000,  // 30 seconds
 *   warnThreshold: 0.8,       // Warn at 80% capacity
 *   captureStackTrace: true,
 *   enableLogging: true,
 *   onLeak: (leak) => {
 *     logger.error('💧 CONNECTION LEAK DETECTED:', {
 *       age: `${leak.age}ms`,
 *       queries: leak.queries,
 *       stackTrace: leak.stackTrace
 *     });
 *
 *     // Send critical alert
 *     monitoring.alert({
 *       type: 'connection_leak',
 *       severity: 'critical',
 *       connectionId: leak.connectionId,
 *       age: leak.age
 *     });
 *   },
 *   onPoolWarning: (context) => {
 *     logger.warn('⚠️  Connection pool capacity warning:', {
 *       active: context.activeConnections,
 *       idle: context.idleConnections,
 *       max: context.maxConnections,
 *       waiting: context.waitingCount
 *     });
 *   }
 * }));
 * ```
 */
export declare function ConnectionLeakDetectorPlugin(options?: ConnectionLeakDetectorOptions): QueryHookPlugin;
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