import type { Row, SqlValue } from '@quereus/quereus';
import type { MergeEntry, MergeConfig } from './merge-types.js';
/**
 * Merges two sorted streams (overlay and underlying) into a single sorted stream.
 *
 * Overlay entries take precedence:
 * - Insert/Update entries replace any underlying row with the same PK
 * - Tombstone entries cause the underlying row to be skipped
 *
 * Both input streams MUST be sorted by the same key (PK for primary scans,
 * index key for secondary index scans). The output stream maintains this ordering.
 *
 * For secondary index scans:
 * - Both streams are ordered by (indexKey, PK)
 * - The merge compares by sort key for ordering
 * - When PKs match, overlay precedence is applied
 *
 * @param overlay Stream of overlay entries (inserts, updates, tombstones)
 * @param underlying Stream of committed rows from underlying storage
 * @param config Comparison and extraction functions
 * @returns Merged stream of rows
 */
export declare function mergeStreams(overlay: AsyncIterable<MergeEntry>, underlying: AsyncIterable<Row>, config: MergeConfig): AsyncGenerator<Row>;
/**
 * Creates a merge entry for an insert or update.
 * @param row The row data
 * @param pk The primary key values
 * @param sortKey The sort key values (defaults to pk if not provided)
 */
export declare function createMergeEntry(row: Row, pk: SqlValue[], sortKey?: SqlValue[]): MergeEntry;
/**
 * Creates a tombstone merge entry for a delete.
 * @param pk The primary key values
 * @param sortKey The sort key values (defaults to pk if not provided)
 */
export declare function createTombstone(pk: SqlValue[], sortKey?: SqlValue[]): MergeEntry;
//# sourceMappingURL=merge-iterator.d.ts.map