Function dbOverwrite

app/redis-6.2.6/src/db.c:225–246

Overwrite an existing key with a new value. Incrementing the reference * count of the new value is up to the caller. * This function does not modify the expire time of the existing key. * * The program is aborted if the key was not already present. */

 *
 * The program is aborted if the key was not already present. */
void dbOverwrite(redisDb *db, robj *key, robj *val) {
    dictEntry *de = dictFind(db->dict,key->ptr);

    serverAssertWithInfo(NULL,key,de != NULL);
    dictEntry auxentry = *de;
    robj *old = dictGetVal(de);
    if (server.maxmemory_policy & MAXMEMORY_FLAG_LFU) {
        val->lru = old->lru;
    }
    /* Although the key is not really deleted from the database, we regard 
    overwrite as two steps of unlink+add, so we still need to call the unlink 
    callback of the module. */
    moduleNotifyKeyUnlink(key,old);
    dictSetVal(db->dict, de, val);

    if (server.lazyfree_lazy_server_del) {
        freeObjAsync(key,old);
        dictSetVal(db->dict, &auxentry, NULL);
    }

    dictFreeVal(db->dict, &auxentry);
}

/* High level Set operation. This function can be used in order to set
 * a key, whatever it was existing or not, to a new object.