[Redis]-使用Lua脚本解决多线程下的超卖问题以及为什么

namespace MengLin.Shopping.Redis.LuaScript { public class SecKillOriginal { static SecKillOriginal( { using (RedisClient client = new RedisClient("127.0.0.1", 6379 { //删除当前数据库中的所有Key, 默认删除的是db0 client.FlushDb(; //删除所有数据库中的key client.FlushAll(; //初始化库存数量为1和订单数量为0 client.Set("inventoryNum", 1; client.Set("orderNum", 0; } } public static void Show( { for (int i = 0; i < 3; i++ { Task.Run(( => { using (RedisClient client = new RedisClient("127.0.0.1", 6379 { int inventoryNum = client.Get<int>("inventoryNum"; //如果库存数量大于0 if (inventoryNum > 0 { //给库存数量-1 var inventoryNum2 = client.Decr("inventoryNum"; Console.WriteLine($"给库存数量-1后的数量-inventoryNum: {inventoryNum2}"; //给订单数量+1 var orderNum = client.Incr("orderNum"; Console.WriteLine($"给订单数量+1后的数量-orderNum: {orderNum}"; } else { Console.WriteLine($"抢购失败: 原因是因为没有库存"; } } }; } } } }

namespace MengLin.Shopping.Redis.LuaScript
{
    public class SecKillLua
    {
        /// <summary>
        /// 使用Lua脚本解决多线程下变卖的问题
        /// </summary>
        static SecKillLua(
        {
            using (RedisClient client = new RedisClient("127.0.0.1", 6379
            {
                //删除当前数据库中的所有Key, 默认删除的是db0
                client.FlushDb(;
                //删除所有数据库中的key 
                client.FlushAll(;

                //初始化库存数量为1和订单数量为0
                client.Set("inventoryNum", 1;
                client.Set("orderNum", 0;
            }
        }

        public static void Show(
        {
            for (int i = 0; i < 3; i++
            {
                Task.Run(( =>
                {
                    using (RedisClient client = new RedisClient("127.0.0.1", 6379
                    {
                        //如果库存数量大于0，则给库存数量-1，给订单数量+1
                        var lua = @"local count = redis.call('get',KEYS[1]
                                        if(tonumber(count>0
                                        then
                                            --return count
                                            redis.call('INCR',ARGV[1]
                                            return redis.call('DECR',KEYS[1]
                                        else
                                            return -99
                                        end";
                        Console.WriteLine(client.ExecLuaAsString(lua, keys: new[] { "inventoryNum" }, args: new[] { "orderNum" };
                    }
                };
            }
        }
    }
}