Trace vs Debug in .NET BCL

Question

It seems that the

are largely the same, with the notable exception that Debug usage is compiled out in a release configuration.

When would you use one and not the other? The only answer to this I've dug up so far is just that you use the Debug class to generate output that you only see in debug configuration, and Trace will remain in a release configuration, but that doesn't really answer the question in my head.

If you're going to instrument your code, why would you ever use Debug, since Trace can be turned off without a recompile?

score 72 · Accepted Answer · answered Oct 07 '08 at 19:07

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The main difference is the one you indicate: Debug is not included in release, while Trace is.

The intended difference, as I understand it, is that development teams might use Debug to emit rich, descriptive messages that might prove too detailed (or revealing) for the consumer(s) of a product, while Trace is intended to emit the kinds of messages that are more specifically geared toward instrumenting an application.

To answer your last question, I can't think of a reason to use Debug to instrument a piece of code I intended to release.

Hope this helps.

answered Oct 07 '08 at 19:07

Jared

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I disagree totally with this answer. Trace is a lower level than Debug and should never be used in production. In my experience, trace is used at the start of methods or "tracing" a piece of work as it passes through a workflow and in some ways, shows the call stack. Everything above and including Info should be the only levels used in production. That is Info, Warning, Error, Fatal. – Razor Jan 09 '13 at 22:12
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I think one other difference is that you can configure [Trace Listeners](http://msdn.microsoft.com/en-us/library/4y5y10s7(v=vs.110).aspx) in your application and route the output of the trace accordingly. The default trace listener in Visual Studio will direct the trace messages to Debug output stream. – orad Jun 11 '14 at 22:23
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Tracing is something that **should** be used in production. It is so important that **every** subsystem of Windows contains tracing code. Every hard drive seek, every memory allocation, every interrupt, CPU context switch, every thread schedule has tracing code baked in. The Event Tracing for Windows platform (ETW) is an extraordinarily lightweight tracing system, that anyone can enable at any time on any Windows PC. The [System.Diagnostics.Tracing.EventSource](https://msdn.microsoft.com/en-us/library/system.diagnostics.tracing.eventsource.aspx) is the managed way to send trace events to ETW. – Ian Boyd Feb 11 '15 at 18:46
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@VincePanuccio I believe you're talking about actual logging levels where this question is talking about the Debug and Trace classes in the System.Diagnostics namespace. You're right thought about the different precedence of each log level. – Ebsan Apr 25 '15 at 18:08
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I've actually got different opinions on Trace these days (4 years later) which is more inline with the answer given by @Jared. Being around a bit longer and looking at how different teams I've worked with use Trace, it's quite useful as an instrumentation tool. MSDN has some great info on the Trace class https://msdn.microsoft.com/en-us/library/system.diagnostics.trace(v=vs.110).aspx Talk about coming around full circle from "I totally disagree" :) – Razor Sep 30 '17 at 06:36
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Microsofts documentation about [Tracing and Instrumenting Applications](https://learn.microsoft.com/en-us/dotnet/framework/debug-trace-profile/tracing-and-instrumenting-applications) helped me to understand the differences even better. – Christoph Sonntag Jan 23 '18 at 10:51
@Razor You might want to delete the first comment. It pops up as the answer to a [question on Google](https://i.ibb.co/myK8Zkk/Screenshot-2021-12-14-135929.jpg). – Sean O'Neil Dec 14 '21 at 22:02

score 5 · Answer 2 · edited Oct 17 '17 at 06:42

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Debug is used to pure debugging purposes. It emits rich messages in debug execution (debug mode).

Trace helps in application debugging, bug fixing, and profiling (after release).

The Debug class is of no use in release mode.

edited Oct 17 '17 at 06:42

Peter Mortensen

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answered Dec 26 '11 at 06:14

Raj

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This is entirely dependant on compilation constants TRACE and DEBUG. – Razor Apr 27 '15 at 11:10
@VincePanuccio The default build settings are what they are because Debug and Trace are intended to be used as this answer indicates. Yes, you can change the TRACE and DEBUG constants to get different behavior, but it's not what the two classes are designed around. – Darryl Sep 27 '17 at 22:52

score 5 · Answer 3 · edited Oct 17 '17 at 06:40

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The only difference between trace and debug is that trace statements are included by default in the program when it is compiled into a release build, whereas debug statement are not.

Thus, the debug class is principally used for debugging in the development phase, while trace can be used for testing and optimization after the application is compiled and released.

edited Oct 17 '17 at 06:40

Peter Mortensen

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answered May 30 '09 at 13:50

sandy101

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This is entirely dependant on the TRACE compilation constant being present, which is the default for Debug and Release. – Razor Apr 27 '15 at 11:09

score 4 · Answer 4 · edited Jan 15 '21 at 00:22

Full difference between Trace and Debug:

Both Debug and Trace use System.Diagnostics namespace.

Debug

It uses Debug class.

It uses in debug build.

It uses the time of application development.

In Debug mode compiler inserts some debugging code inside the executable.

Debug class works only in debug mode.

Performance analysis cannot be done using Debug.

Debugging uses to find error in program.

For Debug we can use Debug.Write() method.

Debug runs in same thread as main program execute.

Trace

It uses Trace class.

Trace statement includes by default when program compiled into released build.

Trace class is used for testing and optimization even after an application is compiled and released.

Trace class works in both case Debug mode as well as release mode.

Trace runs in different thread form main program execute thread.

For Trace we can use Trace.Write() method.

It uses time of application deployment.

Reference: C# Corner

score 2 · Answer 5 · answered Oct 07 '08 at 19:08

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For highly performance sensitive code blocks, leaving Trace compiled-in but disabled might make a performance difference.

answered Oct 07 '08 at 19:08

Kevin Dente

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score 1 · Answer 6 · edited Oct 17 '17 at 06:39

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I'd look at using log4net for tracing as its capabilities are much more flexible and robust.

But for true debug messages that I never intend for anyone other than me or an internal tester to see, I'd probably stick with Debug.

edited Oct 17 '17 at 06:39

Peter Mortensen

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answered Oct 07 '08 at 19:04

Michael Burr

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Question about which loggin framework is preferable shows log4net is not more flexible or robust than others. http://stackoverflow.com/questions/4775194/when-should-i-use-tracing-vs-logger-net-enterprise-library-log4net-or-ukadc-di – Mauro Sampietro Nov 16 '15 at 15:29

score 1 · Answer 7 · edited Jan 15 '21 at 00:24

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You've answered your own question. If Debug messages stayed in, people could see them. For example, let's say you do:

Debug.WriteLine("Connecting to DB with username: blah and PW: pass");

Anyone who decompiles your code can see that. But that may be something vitally important for you to know during testing.

Trace is different. If you are going to do Trace, I'd likely just use log4net.

edited Jan 15 '21 at 00:24

Pang

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answered Oct 07 '08 at 19:07

Cory Foy

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Trace vs Debug in .NET BCL

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