*pinned_tsp = pinned_ts = txn_global->pinned_timestamp;

    /*
     * The read of checkpoint timestamp needs to be carefully ordered: it needs to be after we have
     * read the pinned timestamp and the checkpoint generation, otherwise, we may read earlier
     * checkpoint timestamp before the checkpoint generation that is read resulting more data being
     * pinned. If a checkpoint is starting and we have to use the checkpoint timestamp, we take the
     * minimum of it with the oldest timestamp, which is what we want.
     */
    WT_ACQUIRE_BARRIER();
    checkpoint_ts = txn_global->checkpoint_timestamp;

    if (checkpoint_ts != WT_TS_NONE && checkpoint_ts < pinned_ts)
        *pinned_tsp = checkpoint_ts;