Redis需要你来做的算法优化

阅读一个优秀的Server内核实现，早期的代码比后期的代码要好得多。因为在早期的代码里，你可以学习到一个黑客级别的程序猿到底在思考什么。同时，你能看到他哪里写得差劲，以及后来是怎么优化的。

如果你一心追求最新的技术，但是，不关心它是怎么成长起来的，方向都走错了。走错了方向，跑得越快，离目标越远。

/* Search the first timer to fire.
 * This operation is useful to know how many time the select can be
 * put in sleep without to delay any event.
 * If there are no timers NULL is returned.
 *
 * Note that's O(N) since time events are unsorted.
 * Possible optimizations (not needed by Redis so far, but...):
 * 1) Insert the event in order, so that the nearest is just the head.
 *    Much better but still insertion or deletion of timers is O(N).
 * 2) Use a skiplist to have this operation as O(1) and insertion as O(log(N)).
 */
static aeTimeEvent *aeSearchNearestTimer(aeEventLoop *eventLoop)
{
    aeTimeEvent *te = eventLoop->timeEventHead;
    aeTimeEvent *nearest = NULL;

    while(te) {
        if (!nearest || te->when_sec < nearest->when_sec ||
                (te->when_sec == nearest->when_sec &&
                 te->when_ms < nearest->when_ms))
            nearest = te;
        te = te->next;
    }
    return nearest;
}

Redis在查找最近的时间事件的时候，采用了暴力遍历，时间复杂度是O(N)。优化的方法作者想到了2种，但是他并没有实现，或许他觉得这个不是最紧迫的事情。

需要尝试一下吗？