Question

我正在使用Entity Framework Core运行ASP.NET Core 1.0 Web应用程序。当应用程序运行一段时间（24-48小时）时，应用程序会在每次请求任何端点或静态资源时开始崩溃，从而导致错误System.InvalidOperationException: ExecuteReader requires an open and available Connection. The connection's current state is closed.我只能通过重新启动应用程序池来恢复。< / p>

我正在配置实体框架：

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
        services.AddDbContext<ApplicationDbContext>(options =>
            options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));   
}

我正在使用像这样的扩展方法在owin管道中加载数据：

Startup.cs

app.LoadTenantData();

AppBuilderExtensions.cs：

public static void LoadTenantData(this IApplicationBuilder app)
    {
        app.Use(async (context, next) =>
        {
            var dbContext = app.ApplicationServices.GetService<ApplicationDbContext>();        
            var club = dbContext.Clubs.Single(c => c.Id == GetClubIdFromUrl(context));
            context.Items[PipelineConstants.ClubKey] = club;
            await next();
        });
    }

由于错误仅在应用程序长时间运行时发生，因此很难重现，但我认为它与EF打开和关闭连接错误有关。

我该怎么去调试呢？我错误地使用EF吗？

Answer 1

我遇到了同样的问题。

我认为多个线程可能同时使用相同的dbcontext实例。

你可能需要这个： #include <bits/stdc++.h> #define s 100001 using namespace std; int main() { long long arr[s],i,j,t,m,n; for(i=0;i<s;i++) arr[i] = 1; arr[0] = 0; arr[1] = 0; for(i=2;i<sqrt(s);i++) { if(arr[i] == 1) { for(j=2;i*j<s;j++) arr[i*j] = 0; } } cin >> t; while(t--) { cin >> m >> n; if(n<s) { for(i=m;i<=n;i++) { if(arr[i] == 1) cout << i << endl; } } } return 0; } 有一个问题。 https://github.com/aspnet/EntityFramework/issues/6491

Answer 2

我的应用程序非常基础（快速编写它，运行一次，然后忘记），因此，解决上述问题的方法是在正在执行多表插入的部分周围简单地引入lock。

    public void CallGooglePlacesAPIAndSetCallback(string websiteName)
    {
        using (var db = new WebAnalyzerEntities())
        {
            IList<IRecord> addressesToBeSearched = db.Rent.Where<IRecord>(o => o.Url.Contains(websiteName) && o.SpatialAnalysis.Count == 0).ToList().Union(db.Sale.Where<IRecord>(oo => oo.Url.Contains(websiteName) && oo.SpatialAnalysis.Count == 0)).ToList();
            foreach (var locationTobeSearched in addressesToBeSearched)
            {
                try
                {
           //this is where I introduced the lock
                    lock (_lock)
                    {
                        dynamic res = null;
                        using (var client = new HttpClient())
                        {
                            while (res == null || HasProperty(res, "next_page_token"))
                            {
                                var url = $"https://maps.googleapis.com/maps/api/geocode/json?address={locationTobeSearched.Address}&key={googlePlacesApiKey}&bounds=51.222,-11.0133788|55.636,-5.6582363";
                                if (res != null && HasProperty(res, "next_page_token"))
                                    url += "&pagetoken=" + res["next_page_token"];
                                var response = client.GetStringAsync(url).Result;
                                JavaScriptSerializer json = new JavaScriptSerializer();
                                res = json.Deserialize<dynamic>(response);
                                if (res["status"] == "OK")
                                {
                                    Tuple<decimal?, decimal?, string> coordinatesAndPostCode = ReadResponse(res["results"][0]);
                                    if (coordinatesAndPostCode != null && coordinatesAndPostCode.Item1.HasValue && coordinatesAndPostCode.Item2.HasValue)
                                    {
           //this is the line where exception was thrown
                                        locationTobeSearched.SpatialAnalysis.Add(new SpatialAnalysis() { Point = CreatePoint(coordinatesAndPostCode.Item1.Value, coordinatesAndPostCode.Item2.Value) });
                                        locationTobeSearched.PostCode = coordinatesAndPostCode.Item3;
                                    }
                                }
                                else if (res["status"] == "OVER_QUERY_LIMIT")
                                {
                                    return;
                                }
                            }
                        }
                    }
                }
                catch (Exception e)
                {

                }

                db.SaveChanges();
            }
        }
    }

EF Core - System.InvalidOperationException：ExecuteReader需要一个开放且可用的连接。连接的当前状态已关闭

2 个答案: