/**
 * postgres-mcp — Adapter Metadata Cache
 *
 * TTL-based in-memory cache for schema metadata (table descriptions,
 * index lists). Extracted from `postgres-adapter.ts` to keep that file
 * under the 500-line target.
 *
 * Exported helpers are used exclusively by `PostgresAdapter`.
 */
export declare const DEFAULT_CACHE_TTL_MS: number;
/**
 * Metadata cache entry with TTL support.
 */
export interface CacheEntry<T> {
    data: T;
    timestamp: number;
}
export type MetadataCache = Map<string, CacheEntry<unknown>>;
/**
 * Retrieve a cached value if it has not yet expired.
 * Returns `undefined` on a cache miss or TTL expiry.
 */
export declare function getCached(cache: MetadataCache, key: string, ttlMs: number): unknown;
/**
 * Store a value in the metadata cache with the current timestamp.
 */
export declare function setCache(cache: MetadataCache, key: string, data: unknown): void;
/**
 * Invalidate cached metadata for a specific table.
 * Called after DDL operations that change table structure.
 */
export declare function invalidateTableCache(cache: MetadataCache, tableName: string, schemaName?: string): void;
/**
 * Invalidate all schema-related metadata caches.
 * Used when the specific affected table cannot be determined.
 */
export declare function invalidateSchemaCache(cache: MetadataCache): void;
/**
 * Detect DDL statements and invalidate the appropriate cache entries.
 * Extracts the table name from common DDL patterns; falls back to
 * full schema cache invalidation for ambiguous statements.
 */
export declare function invalidateCacheForDdl(cache: MetadataCache, sql: string): void;
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