/**
 * NOTIFY_HOT (1<<0) 热key
 * NOTIFY_DEL (1<<1) 删除
 * APP_KEY_SPIT "-"  连接符，如goods-skuId:123
 */
void notifySpecialKeyEvent(robj *key, int type) {
    sds chan;
    robj *chanobj, *eventobj;
    int vlen;
    sds *v = sdssplitlen(key->ptr,sdslen(key->ptr), APP_KEY_SPIT,1, &vlen);
    chan = type == NOTIFY_HOT ? sdsnewlen("_keyhot:",8) : sdsnewlen("_keydel:",8);
    chan = sdscatsds(chan, v[0]);
    chanobj = createObject(OBJ_STRING, chan);
    eventobj = createStringObject(v[1],strlen(v[1]));
    pubsubPublishMessage(chanobj, eventobj);
    decrRefCount(chanobj);
    decrRefCount(eventobj);
}

/**
 * 提高衰减速率，衰减到初始值5的时候，再恢复速率，防止内存不足等情况下导致的直接淘汰
 * 注：实际场景下 要监控redis内存 一般不会触发LFU淘汰
 */
unsigned long LFUDecrAndReturn(robj *o) {
    unsigned long ldt = o->lru >> 8;
    unsigned long counter = o->lru & 255;
    unsigned long num_periods = server.lfu_decay_time ?
                  LFUTimeElapsed(ldt) / server.lfu_decay_time : 0;
    if(num_periods){
        if(counter == LFU_INIT_VAL)
            return (num_periods> counter) ? LFU_INIT_VAL : counter - num_periods;
        return (num_periods * 30  > counter) ? LFU_INIT_VAL : counter - num_periods * 30;
    }
    return counter;
}

  { 
     "delpush",delpushCommand,-2,
     "write fast @keyspace",
     0,NULL,1,-1,1,0,0,0
  }


/**
 * 指令执行
 */
void delpushGenericCommand(client *c) {
    int numdel = 0, j;

    for (j = 1; j < c->argc; j++) {
        expireIfNeeded(c->db,c->argv[j]);
        int deleted = dbAsyncDelete(c->db,c->argv[j]) ;
        if (deleted) {
            signalModifiedKey(c,c->db,c->argv[j]);
            notifySpecialKeyEvent(c->argv[j], NOTIFY_DEL);
            server.dirty++;
            numdel++;
        }
    }
    addReplyLongLong(c,numdel);
}