使用默认SQL实例时的实体框架代码优先超时

Question

I am seeing strange timeout behavior when connecting to a SQL Server 2012 Express default instance using Entity Framework - tested on 5.0.0 and 6.0.0.

If I use a server, by IP address, that is offline, EF seems to ignore any timeout values in the connection string.

This connection string always takes 73 seconds to timeout:

<connectionStrings>
<add name="TestContext" connectionString="Server=10.0.0.2;Database=TestDb;User ID=sa;MultipleActiveResultSets=True;Connection Timeout=5" providerName="System.Data.SqlClient" />

If I add a port, it takes 42 seconds:

<connectionStrings>
<add name="TestContext" connectionString="Server=10.0.0.2,1433;Database=TestDb;User ID=sa;MultipleActiveResultSets=True;Connection Timeout=5" providerName="System.Data.SqlClient" />

And any connectionstring with hostname takes 14 seconds, but if DNS resolves and host is offline; or online host doesn't have a SQL instance, it's back to 73 seconds eg

<connectionStrings>
<add name="TestContext" connectionString="Server=dev-pc;Database=TestDb;User ID=sa;MultipleActiveResultSets=True;Connection Timeout=5" providerName="System.Data.SqlClient" />

I have tried:

context.Database.CommandTimeout = 5;

with no change in results. This was expected since it doesn't even make it to the query.

Here is my inherited DbContext class:

namespace Test.DataLayer
{
    public class TestContext: DbContext
    {
        public DbSet<Person> People { get; set; }           

        static TestContext()
        {
            Database.SetInitializer<TestContext>(null);
        }    

        public TestContext()
            : base("Name=TestContext"){}           
    }
}

Questions:

Is this expected Entity Framework (or underlying provider) behavior?

Which timeout does it follow in this situation?

Since a 73 second timeout is too long, what can be done to speed up detection of offline SQL hosts?

Any other comments or suggestions will be appreciated.

Thanks,

Francois

Answer 1

CommandTimeout controls the time it waits for a specific command to execute (a SELECT for example); it will not have any impact when the server is unreachable and no command has been sent. Try ConnectionTimeout and see if it makes any difference.