To audit EF queries, we'll install and use a tool called Glimpse.

Once installed, Glimpse will give us the ability to easily inspect web requests,

including the EF queries that are executed.

To install Glimpse, we use the NuGet Package Manager.

Select the Browse tab and search for Glimpse.

Glimpse is the main base package, so we'll start with installing that.

When the Glimpse package is finished installing, it'll open a Readme file that

contains information on how to get started with using Glimpse.

To get the most out of using Glimpse with our web app,

we'll install two additional Glimpse packages.

The Glimpse EF6 package, for auditing Entity Framework queries and commands, and

the Glimpse Mvc5 package, for auditing events related to the MVC web framework.

Since the Glimpse EF6 package is right here in this list,

let's start with installing that.

Then, search for Glimpse.mvc, and

install the Glimpse.Mvc5 package.

Every time that you install a Glimpse related package,

the installer will inspect your Glimpse packages, and update the Readme file to

let you know if any are out of date, and need to be updated.

Looks like there's an update for the Glimpse.AspNet package.

Let's select the Updates tab, and update the package.

Now that we have all of the necessary packages installed, we can run our

application and configure Glimpse by browsing to the path glimpse.axd.

Glimpse.axd looks like it'd be a file in our project, but it's not,

it's a special path that maps to the Glimpse HTTP handler.

In the Web.config file that's located in the root of our project,

we can see the HTTP handler configuration that was added

when we installed the Glimpse NuGet package.

The way that ASP.NET handles processing requests can be customized through the use

of custom HTTP handlers or modules, Glimpse makes use of both.

For more information about HTTP handlers and modules, see the teacher's notes.

To enable Glimpse, we simply click the large Turn Glimpse On button.

Once the page is reloaded, we can see here on the right,

in this green box, that the Glimpse cookie is set to on.

An HTTP cookie is a little piece of data that the browser sends to the web server

on every request.

Glimpse uses a cookie to determine when it's enabled.

For more information on cookies, see the teacher's notes.

Now that we've enabled Glimpse, we can remove glimpse.axd from our path,

to return to our web app's home page.

And here's our home page, but notice here in the lower-right,

we now have the glimpse Heads-Up Display, or HUD, being displayed.

The glimpse HUD will give us some basic information about our request,

how long the request took to complete in milliseconds.

And a breakdown of how much time that was spent communicating between the client and

the server, processing on the server, and processing on the client.

We can also see a breakdown of the server processing time,

how much spent in the action method, and rendering the view.

We can also see which controller and action was called, and

just to right of that, how many database queries were ran, and how long they took.

We can hover over each section to get a quick look at some additional information.

Here's a closer look at the HTTP section, And the Host section.

Clicking on the g in the lower right-hand corner opens up the full Glimpse panel.

Glimpse gives you detailed information about the request.

For now, let's select the SQL tab, and take a look at

the information that Glimpse provides about EF queries and commands.

We can see that a single query was executed, and

how long it took to complete, and the SQL that EF generated for the query.

Let's look at another example by browsing to the ADD COMIC BOOK page.

Now, we can see that 3 queries were executed, and the total execution time.

Then, below that, we can see the SQL for each query, and

how long each took to execute.

Glimpse is a powerful, easy-to-use tool that can help you to not only understand

how a request is being processed, but how each part is performing.

We'll continue to use Glimpse throughout the rest of this workshop,

as we take a closer look at some common EF query performance issues.