Disable EF Core Migration verification query

问题

I'm running an asp.net core 2.1.4 web application with entity framework core 2.1.4 using code first. The migration and seed are done on application startup.

I've noticed a couple of EF queries checking for checking the migration history on every call:

Executed DbCommand (47ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT OBJECT_ID(N'[__EFMigrationsHistory]');

Executed DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT OBJECT_ID(N'[__EFMigrationsHistory]');

Executed DbCommand (4ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT [MigrationId], [ProductVersion] FROM [__EFMigrationsHistory] ORDER BY [MigrationId];

No migrations were applied. The database is already up to date.

I don't want to check the database on every call. So I changed the ServiceLifetime.Singleton. But still I see this verification queries on every call.

services.AddDbContext<ApplicationDbContext>(options =>
{
    options.UseSqlServer(dbConnectionString,
        builder => builder.MigrationsAssembly(migrationsAssembly));
}, ServiceLifetime.Singleton, ServiceLifetime.Singleton);

There is a similar question on EF6: How to disable Migration Verification during every DbContext initialization

The NullDatabaseInitializer doesn't exist in EF core.

What is recommended to do? Is this normal behavior?

回答1:

I found the issue: https://github.com/Microsoft/ApplicationInsights-aspnetcore/issues/778

After using a "real" SQL profiler I found out it was working as expected like @Ivan-Stoev said. The requests on my side were somehow using the same operation_id. So the traces and dependencies that where shown to me by application insights where actually not related.

I fixed it by removing the default DependecyTracking of AI.

private void RemoveDefaultAiDependencyTracking(IServiceCollection services)
{
    var serviceDescriptor = services.FirstOrDefault(descriptor => descriptor.ImplementationType == typeof(DependencyTrackingTelemetryModule));
    services.Remove(serviceDescriptor);
}

Thanks for you time and sorry for wasting it..

来源：https://stackoverflow.com/questions/53322973/disable-ef-core-migration-verification-query

标签

entity-framework-core

azure-application-insights