swift - 如果结果限制小于 1000，为什么我的 CKQueryOperation 只会返回 Cursor？

Question

CloudKit 有大约 2000 条记录我正在尝试下载。我无法全部下载，我查看了 CloudKit CKQueryOperation doesn't get all records获得超过 100 个结果。现在我最多可以下载 999 个，但如果我将结果限制设置为 1000 或更多，它将在 80-500 之间随机失败。我需要将这些条目拆分为不同的记录类型吗？

private func checkForCloudData() {
    let query = CKQuery(recordType: "myRecordType", predicate: .init(value: true))
    let op = CKQueryOperation(query: query)

    op.qualityOfService = .userInitiated
    op.queuePriority = .veryHigh
    op.resultsLimit = 999

    op.recordFetchedBlock = { record in
        // fetched record
    }

    op.queryCompletionBlock =  { cursor, err in

        if cursor != nil {
            print(cursor!)

            self.performOperation(withOperation: CKQueryOperation(cursor: cursor!))
        }

        if err == nil {
            // handle complete download
        } else {
            if (err as! CKError).code == .limitExceeded {
                if cursor != nil {
                    self.performOperation(withOperation: CKQueryOperation(cursor: cursor!))
                    return
                }
                let newOperation = CKQueryOperation(query: query)
                newOperation.resultsLimit = op.resultsLimit
                newOperation.queuePriority = .veryHigh
                newOperation.qualityOfService = .userInitiated
                newOperation.recordFetchedBlock = op.recordFetchedBlock
                newOperation.queryCompletionBlock = op.queryCompletionBlock

                self.performOperation(withOperation: newOperation)
            }
        }

    }

    self.performOperation(withOperation: op)
}

private func performOperation(withOperation operation: CKQueryOperation) {
        publicDB.add(operation)
}

Answer 1

我认为400是单次操作的限制，因此您需要使用游标来获取更多记录，并在返回游标不为nil时继续这样做。

看看它是如何在 RxCloudKit 库的 RecordFetcher 中完成的 - https://github.com/maxvol/RxCloudKit/blob/master/RxCloudKit/RecordFetcher.swift