Question

我目前正在构建一个网站，我刚刚使用LinqToSQL实现了SqlCacheDependency。

   public IQueryable<VictoryList> GetVictoryList()
   {
                string cacheKey = HttpContext.Current.User.Identity.Name + "victoryCacheKey";
                IQueryable<VictoryList> cachednews = (IQueryable<VictoryList>)HttpContext.Current.Cache.Get(cacheKey);

                if (cachednews == null)
                {

                    var results = from v in _datacontext.ViewVictoryLists
                                  orderby _datacontext.GetNewId()
                                  select new VictoryList
                                  {
                                      MemberID = v.MemberID,
                                      Username = v.Aspnetusername,
                                      Location = v.Location,
                                      DaimokuGoal = v.DaimokuGoal,
                                      PreviewImageID = v.PreviewImageID,
                                      TotalDaimoku = v.TotalDaimoku,
                                      TotalDeterminations = v.TotalDeterminations,
                                      DeterminationID = v.DeterminationID,
                                      DeterminationName = v.DeterminationName
                                  };
                    SqlCacheDependency dependency =
                     new SqlCacheDependency(_datacontext.GetCommand(results) as SqlCommand);

                    HttpContext.Current.Cache.Add(cacheKey, results, dependency, DateTime.MaxValue,
                                  TimeSpan.Zero, CacheItemPriority.Normal, null); 

                    return results.ToList().AsQueryable();
                }
                return cachednews;
   }

它似乎正在工作，因为事情明显更快，特别是在一些复杂的查询上，但是在查看SQLProfiler中的事情时我仍然看到查询运行，我正在使用SqlCacheDependency的CommandBroker模式。即使数据显然来自缓存对象，我还应该看到查询吗？

Answer 1

我认为问题在于您将IQueryable存储在缓存中，然后cachednews包含一个可以访问数据库的IQueryable。

尝试以下更改。

public IQueryable<VictoryList> GetVictoryList() {
            // ...
            if (cachednews == null)
            {

                var results = from // ...
                results = results.ToList().AsQueryable(); // force query execution

                SqlCacheDependency dependency = // ...;
                HttpContext.Current.Cache.Add(cacheKey, 
                    results, // now just the result are stored
                    dependency, 
                    DateTime.MaxValue,
                    TimeSpan.Zero, 
                    CacheItemPriority.Normal, 
                    null); 

                return results;
            }
            return cachednews;
}

我是否仍然可以在SQL事件探查器中看到查询？

1 个答案: