import type { EmbeddingCacheEntry, EmbeddingCacheStore } from '../types/embeddings.js';
import type { MigrationResult, SchemaMigration } from '../utils/schema-migrations.js';
import { type PostgresLikeClient } from './client.js';
import type { PostgresMigrateOptions } from './migrations.js';
/** Options for the Postgres embedding cache. */
export interface PostgresEmbeddingCacheOptions {
    /** The table, optionally schema-qualified. Defaults to `nexus_embedding_cache`. */
    table?: string;
}
/** The versioned schema, which `migrate()` and `nexus db migrate` apply. */
export declare function embeddingCacheMigrations(options?: PostgresEmbeddingCacheOptions): SchemaMigration[];
/**
 * Vectors in a Postgres table, shared by every process that reaches the database. A batch is one
 * `SELECT` and one upsert, and a vector is packed float32: 6 KB for 1,536 dimensions.
 */
export declare class PostgresEmbeddingCache implements EmbeddingCacheStore {
    private readonly client;
    private readonly options;
    private readonly table;
    constructor(client: PostgresLikeClient, options?: PostgresEmbeddingCacheOptions);
    /** Applies the table's pending migrations. Never runs implicitly. */
    migrate(options?: PostgresMigrateOptions): Promise<MigrationResult>;
    /** The vectors under these keys, in order, with `undefined` for each miss or expired entry. */
    getMany(keys: readonly string[]): Promise<Array<number[] | undefined>>;
    /** Stores vectors, each for `ttlSeconds` when given. */
    setMany(entries: readonly EmbeddingCacheEntry[], ttlSeconds?: number): Promise<void>;
    /** Deletes expired vectors, returning how many went. */
    purgeExpired(): Promise<number>;
}