46、对等网络数据管理与副本一致性技术解析

对等网络数据管理与副本一致性技术解析

1. 范围查询算法 BatonRange

在对等网络数据管理中，范围查询是一项重要操作。BatonRange 算法用于处理范围查询，其输入为形如 [a, b] 的范围查询 Q ，输出为结果关系 T 。以下是该算法的具体代码：

Algorithm 9.7: BatonRange
Input: Q: a range query in the form [a, b]
Output: T: result relation
begin
    {Search for the peer storing the lower bound of the range}
    At query originator peer
    begin
        find peer p that holds value a
        send Q to p
    end
    for each peer p that receives Q do
        Tp ← Range(p) ∩ [a, b]
        send Tp to query originator
        if Range(RightAdjacent(p)) ∩ [a, b] ̸= ∅ then
            let p be right adjacent peer of p
            send Q to p
        end if
    end for
end