# fetchIdentifiers(_:batchSize:) Returns a collection of persistent identifiers, in batches, where each identifier represents a single model that satisfies the criteria of the specified fetch descriptor. ``` func fetchIdentifiers(_ descriptor: FetchDescriptor, batchSize: Int) throws -> FetchResultsCollection where T : PersistentModel ``` ## Parameters `descriptor` A fetch descriptor that provides the configuration for the fetch. `batchSize` The maximum number of identifiers to include in each batch. ## Return Value The collection of persistent identifiers. If no models match the descriptor’s criteria, the array is empty. ## Discussion The collection automatically fetches subsequent batches as you iterate over the identifiers, or access one at a specific index. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)