Debugging Entity Framework SQL statements

Question

I am having a weird pattern of response time when using the Entity Framework for SQL communication.

This is from my web host:

This is from my local server:

It's the increase in response time I am worried about. I have narrowed the problem down to one single line in code Nop.Data > EfRepository.cs > public void Insert(T entity) > _entities.Add(entity); Yes I know this very specific for the NopCommerce, but the point is really that I am looking her for help on how to debug this.

Are there some events I can catch that display the SQL being executed? Or what other things can I do to find out more what is actually happening in the Entity Framework in that above command.

JohnD · Answer 1 · 2013-03-27T15:33:57.143

For debugging EF queries, the easiest thing is to cast the query to ObjectQuery and use ToTraceString:

var query = myContext.MyTable
    .Where(r => r.Id == searchId)
    .Select(r => r);

Console.WriteLine(((ObjectQuery)query).ToTraceString());

This will show the underlying SQL for the query, and you can run the queries manually to debug why they are slow. Here is the MSDN link:

http://msdn.microsoft.com/en-us/library/system.data.objects.objectquery.totracestring.aspx

If you're trying to get the SQL which is run when you call SaveChanges() on your context, it's not as easy. You could take a look at EFTracingProvider:

http://blogs.msdn.com/b/jkowalski/archive/2009/06/11/tracing-and-caching-in-entity-framework-available-on-msdn-code-gallery.aspx

Or, assuming you use SQL Server, you can go directly to SQL Profiler and capture the T-SQL statements (this is my preferred approach).

Thanks, I will try the first one because the SaveChanges() call does not seem to take that much time, at least the line I wrote took alot of time. I cannot not use the Profiler (I tried) due to restrictions on the host. — Anders, Oct 26 '11 at 12:47
I found out that part of the problem was within the code regarding casting of objects to specific classes. So the problem probably was not SQL related — Anders, Nov 16 '11 at 21:08

score 14 · Answer 2 · answered Apr 24 '15 at 14:02

In EF6, you can also do this in the constructor of your dbcontext

Example

public BookServiceContext() : base("name=BookServiceContext")
{
    // New code:
    this.Database.Log = s => System.Diagnostics.Debug.WriteLine(s);
}

This will log to the console every SQL query EF generates. See this article for more information http://blog.oneunicorn.com/2013/05/08/ef6-sql-logging-part-1-simple-logging/

score 0 · Answer 3 · answered Aug 17 '22 at 12:58

0

Another example might be very helpful for someone.

public class MyDbContext : DbContext
{
    private readonly ILoggerFactory _loggerFactory;

    public MyDbContext(DbContextOptions<MyDbContext> options, ILoggerFactory loggerFactory) : base(options)
    {
        _loggerFactory = loggerFactory ?? throw new ArgumentNullException(nameof(loggerFactory));
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        // Enable logging
        optionsBuilder.UseLoggerFactory(_loggerFactory);

        if (System.Diagnostics.Debugger.IsAttached)
            optionsBuilder.EnableSensitiveDataLogging();

        base.OnConfiguring(optionsBuilder);
    }
}

answered Aug 17 '22 at 12:58

ADM-IT

3,719
1
25
26

Fortunately, that's become a lot easier now. See the newer answer. – Gert Arnold May 06 '23 at 14:05
Gert Arnold, I don't think you should write logs into the console. Also see `EnableSensitiveDataLogging`. The right way is to pass the logger. Then you can setup your logger whatever (sql, system, io) and wherever (file, console, db) you want to log using appsettings.json. – ADM-IT May 13 '23 at 10:19
You don't have to log to the console, it's just an example. And sensitive data logging can be en/disabled in the `optionsBuilder` apart from logger factory options. – Gert Arnold May 13 '23 at 11:26

score 0 · Answer 4 · answered May 06 '23 at 13:44

0

EF 7:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    base.OnConfiguring(optionsBuilder);
    optionsBuilder
        .UseSqlServer("...")
        .LogTo(Console.WriteLine, LogLevel.Information);
}

answered May 06 '23 at 13:44

Ilia

147
1
7

Debugging Entity Framework SQL statements

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