The total number of checkpoints. The total checkpoints
    category is further broken down into categories of reasons for
    checkpointing. The statistics for these categories are included
    in the "AIJ growth," "txn limit," "time limit," "rollback," "AIJ
    backup," and "global" subfields.

    Note that there may be more reasons for checkpoints than there
    are total checkpoints. For example, you might have a total count
    of 100 for checkpoints, but when you add the number of checkpoint
    reasons ("AIJ growth," "txn limit," "time limit," "rollback,"
    "AIJ backup," and "global"), the total could be greater than 100.
    This occurs because a single checkpoint may be triggered by more
    than one event. For example, a checkpoint may occur because of
    time and AIJ file growth. Although the total count columns for
    the "interval: seconds" and "interval: AIJ blks" fields are both
    incremented by one, the total count column for "checkpoints" is
    only incremented by one.