实体框架数据库初始化:初始化新Azure SqlDatabase时超时

Question

我有一个ASP.NET MVC应用程序.通过CustomerController创建新客户时,我运行新的后台任务(使用HostingEnvironment.QueueBackgroundWorkItem)为该客户创建新的Azure SqlDatabase.

我使用Entity Framework Code First来创建/初始化新数据库.这是代码:

// My ConnectionString
var con = "...";

// Initialization strategy: create db and execute all Migrations
// MyConfiguration is just a DbMigrationsConfiguration with AutomaticMigrationsEnabled = true
Database.SetInitializer(strategy: new MigrateDatabaseToLatestVersion<CustomerDataContext, MyConfiguration>(useSuppliedContext: true));

using (var context = new CustomerDataContext(con))
{
    // Neither 'Connection Timeout=300' in ConnectionString nor this line helps -> TimeoutException will rise after 30-40s
    context.Database.CommandTimeout = 300;

    // create the db - this lines throws the exception after ~40s
    context.Database.Initialize(true);
}

我的问题是我总是在大约40秒后得到一个TimeoutException.我认为这是因为Azure无法在这么短的时间内初始化新数据库.不要误会我的意思:Azure将很好地创建数据库,但我想等待那一点/摆脱TimeoutException.

Edit1: 我在ConnectionString中使用Connection Timeout = 300但我的应用程序并不真正关心它; 大约40年后,我总是遇到一个SqlError.

Edit2: 引发的异常是SqlException.消息:超时已过期.操作完成之前经过的超时时间或服务器没有响应.来源:.Net SqlClient数据提供程序

编辑3: 我现在可以确定这与ASP.NET/IIS无关.即使在简单的UnitTest方法中,上面的代码也会失败.

Answer 1

在使用Code First Migrations时,似乎还有另一个CommandTimeout设置涉及数据库初始化过程.我想在这里分享我的解决方案,万一有人遇到这个问题.

感谢Rowan Miller的暗示,他指出了我的解决方案.

这是我的代码:

// Initialisation strategy
Database.SetInitializer(strategy: new CreateDatabaseIfNotExists<MyDataContext>());

// Use DbContext
using (var context = new MyDataContext(myConnectionString))
{
    // Setting the CommandTimeout here does not prevent the database
    // initialization process from raising a TimeoutException when using
    // Code First Migrations so I think it's not needed here.
    //context.Database.CommandTimeout = 300;

    // this will create the database if it does not exist
    context.Database.Initialize(force: false);
}

我的Configuration.cs类:

public sealed class Configuration : DbMigrationsConfiguration<MyDataContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
        AutomaticMigrationDataLossAllowed = false;

        // Very important! Gives me enough time to wait for Azure
        // to initialize (Create -> Migrate -> Seed) the database.
        // Usually Azure needs 1-2 minutes so the default value of
        // 30 seconds is not big enough!
        CommandTimeout = 300;
    }
}