An Identity Crisis: Is it Profiler or is it Extended Events?
I have been working on this article for far longer than one might think is necessary for something of this nature. Truth be told, I was reluctant because there are so many people that quickly jumped on the wagon to write about this feature as soon as it was released. With some coercing, here the article is finally!
What is this newfangled feature? Well, that is kind of the problem. The name has already changed in the second release – be it ever so slightly. The feature is XE Profiler or XEvents Profiler and in theory it is supposed to give us something new in management studio.
Fact or Fiction
This Extended Events Profiler is a brand spanking new feature (ok, so the bouncing baby is a few months old now and no longer a newborn). Despite it being new, it seems there are a handful of “facts” already published about it that may or may not be accurate. Due to that, I want to play a little game of fact or fiction with it in this article.
Here is the short list from which we will work:
- Sessions (XE Profiler Sessions) are Customizable
- The default standard session displays all Extended Events
- It works with instances of SQL 2012 or greater only
- XE Profiler Adds ability to quickly start/stop sessions
- XE Profiler provides a new live view of the Event Session
- XE Profiler provides a GUI for Extended Events
- Templates were not available in XE until the release of XE Profiler
- Similarly, XE Profiler also brought the Profiler templates with it as part of the feature release
- A DBA can now do something that was not previously possible to do (quickly start a session)
That is a rather wealthy list of “facts” to be checked for validity if you ask me. Let’s go ahead and start diving into each of these. I will not be following the provided list order. Rather, I will be looking at items that seem appropriate to validate in my own special order. Rest assured tho, we will get through the list.
I don’t know how this is still a misconception about Extended Events, but it is certainly still out there. Suddenly XE Profiler comes along and people suddenly think that this tool has provided the GUI that everybody has been clamoring about since Extended Events was released in 2008 (yes almost 10 yrs ago).
I am not going to waste much time on this because it is a complete and total piece of fiction. The GUI has been readily and easily available since SQL Server 2012. In addition to that, there was a GUI that could have been installed for the older versions that was created by Jonathan Kehayias.
From SSMS 2014, here is a sample screenshot of the GUI wizard followed by a standard GUI screen.
As you can see, there is clearly a GUI prior to the release of SSMS 17.3.
This is probably the next easiest notion to prove or disprove. I have heard from more than a single source that templates are brand new with SSMS 17.3 (which is when XE Profiler was released).
I don’t really need to go very far or work very hard to prove this notion as a complete work of fiction. I have SSMS 2014, 2016, 17.0, 17.3, and 17.4 readily available to me. I am going to start with SSMS 2014.
If I once again open the GUI for XEvents in SSMS 2014, I can easily see the available templates in that version.
It looks pretty obvious there that templates were introduced well before SSMS 17.3.
I can also see all of the templates available by browsing out to the file system.
And for good measure, here is one from a 2012 instance.
The same templates (minus possible changes within the template definitions) are available in SSMS 2012, 2014 and 2016. We will see those same templates available in SSMS 17 and above as well – in addition to a few that have been added.
I want to also add here that these are just the default templates. Just like in Profiler, you can create and save your own templates for future use.
We just saw how there are templates available prior to the release of SSMS 17.3. We can also see that the profiler templates are not available in those prior versions of SSMS. So does that also mean that the profiler templates were only released as a part of SSMS 17.3? We best be careful with that slippery slope of assumption. Let’s take a closer look at SSMS 17.0.
And just so we can confirm that this is indeed a version of SSMS that pre-dates 17.3…
As you can see there, this is RC3 of SSMS 17.0 so it is definitely a version that precedes 17.3
And similarly from a peek inside the folder on disk:
Seems to me we have ample evidence that the profiler templates were made available to the XE GUI well in advance of SSMS 17.3
Event Session Live View
One of the most widely used feature of profiler is the ability to watch the data as it streams through the session. According to many, this ability is missing in Extended Events and the XE Profiler feature has brought this ability to the forefront with XE now.
Let’s start by taking a look at an XE Session in SSMS 2014 connected to a 2014 database instance to check the validity of this concern.
All I need to do is browse the nodes in SSMS down to the session I want to view. Right click the session and then select the option to “Watch Live Data”.
After clicking watch live data, the event session live stream will appear on the right and start streaming the data to your SSMS workspace as shown in the following image.
For this session demo, I selected a session that should be readily available to everybody – the system_health default session. That session comes installed and running for you already.
Don’t like the layout of the screen? Well, you can customize the view to your liking and it can be customized differently for each and every different running session on your server.
As it turns out, the ability to watch livestream data has been available to you for Extended Events since 2012 when the GUI was made available. If you are curious about learning more about the GUI and customizing the view, you can read various articles I have written in my 60 day series you can find here.
That brings us to the halfway point. To recap we are now sitting at a score of Fact 0 and Fiction 4. Let’s see if we can turn the tide in these last 5.
Quick Start a Session
To be quite frank here, this has been a long time argument against using Extended Events. It just isn’t possible to start a session quickly and easily. I have two methods that I have shown in my training sessions concerning that concern. Let’s take a look at the first. I will demonstrate this from SSMS 2014.
The first thing that needs to be done is browse the SSMS tree until a session is found that you want to start. Here is an ancient cheat code – I leave many sessions on the server in the stopped state until I need to use them. Pro-tip: create your XE sessions on all of your servers and leave them stopped until you think you need to use it.
For this example, I have selected my AG_LeaseTimeout sessions which is in the stopped state (denoted by the little red “stop” icon next to the session name).
Then right click the session name and select “Start Session” from the context menu. To help clarify, I have circled the session name in green and the menu item in blue. This an extremely easy method to start a session. Once started, and if you really feel you must watch data stream onto the screen, then you can also follow the steps shown for watching the live stream data in the previous section.
The second method to quick start a session is only a touch more difficult. The steps are just the same as shown in the “template” section. You select a template that matches your desires and give the session a name. Here are some broad strokes shown in SSMS 17.0 (same steps apply for SSMS 2014 minus the ability to select a profiler template):
Right click the “Session” node and selection “New Session” from the context menu.
Select the “Standard” template from the dropdown box. This is a profiler equivalent (and also happens to be one of the two default sessions in “XE Profiler” so makes sense for a good comparison. Note that the window has a warning that the Session name cannot be empty, so let’s give the session a name.
With that warning cleared, we can now move on to the next configuration. Notice the two red arrows in the preceding image. Enabling these two options will start the session immediately and also give you that profiler warm and fuzzy by allowing you to immediately start watching the session without needing to lift another finger.
From here, click the OK button ( I know I normally teach people that they should script it, but in this case we are going for quick and easy). After clicking “ok”, be prepared for something like the following.
After just a few seconds on a busy server, one should expect thousands of events to fire in a very profiler type manner. I want to reiterate here, that this was the same session template that feeds one of the two available sessions in XE Profiler.
Once you have determined that you have enough data, you can easily stop the session by right clicking the session name and then selecting the “Stop Session” menu item.
And that is all. It is very easy to start a session in two different manners without XE Profiler. One of the options even allows you to create the exact same session as XE profiler but without that feature even being made available on the version of SSMS being used. So if you really want that profiler type of session, you can use a template to quickly create it even if your SSMS version pre-dates 17.3 and even if you don’t have the profiler templates by default (remember you can simply add the profiler templates should you choose).
In the end, I have to call this one a piece of fiction as well. The XE Profiler does not add any new ability to quickly start a session that wasn’t already a viable option. That said, the XE Profiler does add a third alternative to start a session – so long as it is one of the two default sessions.
SQL 2012 Required
This is one of those areas that I wish were fiction. However, this has actually been a consistent theme ever since the GUI was released for XE. The GUI components only work on 2012 instances and later. Let’s take a look at a connection to a 2014 Server and a 2008R2 Server in the same SSMS window from SSMS 17.0.
We can see here that the standard Extended Events GUI is just not available for the 2008R2 instance. The 2014 instance is denoted with a Green box and arrow to help distinguish between that and the red marks for the 2008R2 instance.
Now, let’s take a look at it with SSMS 17.3. With a similar setup and similar notation, we see the following in SSMS 17.3 when connected to both a 2014 instance and a 2008R2 instance.
Once again, I will admit this is something I really wish were not the case. It would definitely be helpful if the XE GUI were to be made available to SQL Server Instances that are 2008 and 2008R2. Especially given that the tool is an “SSMS feature”. That said, it really behooves everybody to get their SQL Servers updated to current technologies (2008 is nearly 10 years old afterall).
The default “Standard” session displays all Extended Events
So far, we have been easing ourselves into this XE Profiler very gently. It is time to finally get into the deeper end and actually look at some very specific XE Profiler things. When I first heard this one, I was admittedly flabbergasted. One session displays all extended events? Really? Let’s actually establish some baselines about the default sessions for XE Profiler first.
- There are only two default sessions for XE Profiler
- The session names are “Standard” and “TSQL”
- The default sessions are based on templates (discussed previously)
- The template for the “Standard” session is the xe_Profiler_Standard xml template file
- The template for the “TSQL” session is xe_Profiler_TSQL
If I peruse the template file located in the directory on disk (C:\Program Files (x86)\Microsoft SQL Server\140\Tools\Templates\sql\xevent) for the standard session, I will be able to see that it contains the following events:
<event package="sqlserver" name="attention">
<event package="sqlserver" name="sql_batch_starting">
<event package="sqlserver" name="sql_batch_completed">
<event package="sqlserver" name="rpc_completed">
<event package="sqlserver" name="existing_connection">
<event package="sqlserver" name="logout">
<event package="sqlserver" name="login">
Now, that is not the entire template file. I shorted it to only include the events and none of the other details like session configuration or the actions attached to each event. As you can see, there is a grand total of seven events in this particular session.
If I run the following statement against a SQL Server 2014 instance, I will get a few more events than just seven.
SELECT SERVERPROPERTY('ProductMajorVersion') AS SvrVersion,COUNT(*) AS EventCount
FROM sys.dm_xe_objects xo
WHERE xo.object_type = 'event';
And the results:
And just for the sake of clarity, the results on a 2017 instance:
Obviously the math does not add up. There are multiple things wrong with the notion that a session from XE Profiler will contain all events. First, there is no sense at all in adding every event to a single event session. The second problem is that the session is supposed to mimic a profiler default template session. If it is supposed to mimic a profiler style session, you can only use 180 events max anyway. Profiler only had 180 events and XE is obviously way beyond that with so much more feature support than Profiler could even muster back in its glory days.
In case, you were wondering, here is how you access the XE Profiler. It is not under the Extended Events Node, it is a brand new node.
As you can see, there really are only the two options for XE Profiler and if you recall, both of those options are derived from the templates that were made available in the traditional XE GUI and are very easy to create a quick session via the same templates as these two options.
Whether using the XE Profiler or the previous method to create these sessions, there is just no way that these sessions could contain every event in Extended Events. It’s just a bunch of hot air with no foundation to the claim.
XE Profiler adds ability to start/stop session
Let’s start back with the last image from the previous section and then go from there. We need to access what is available to us via the XE Profiler node so we can test this theory. I will start by right clicking one of the sesisons (right clicking on the “XE Profiler object itself will not yield anything very promising fwiw).
As you can see here, we are given some pretty basic options to either “Stop Session” or to “Launch Session”. It also seems very obvious what they want you to do here because the option is bolded – “Launch Session”.
This menu is the same regardless of the session state. What I mean by that is even if you do not have the session created, this menu is the same as if you have the session created and running. None of the options dim and all are clickable on this menu. This holds true for SSMS 17.4 as well. Let’s take a look at a server where none of these “profiler” sessions are running.
I want to make it abundantly clear. This is the way it appears after a completely fresh install of SSMS 17.3. None of these sessions have ever run on this particular instance of SQL Server 2017 and this is even a completely fresh install of SQL Server 2017. That said, I have done nothing yet to break it – buahaha.
Knowing that no sessions have ever been “launched” for XE Profiler, it is clear that it is time to go ahead and “launch” a session. In this new feature “launch” is the new equivalent of “start”. Once you launch a session you will get the same net effect as what we saw earlier when I created a session from the profiler template and checked the box to watch live data and the box to start the session. When I click launch, I will see something like the following:
A new XE session was created under the Extended Events node and it is now called “QuickSessionStandard”. Once again, this is created from that profiler template I have mentioned a few times.
And then after a bit, I may want to try and stop the session.
You can see here that I was able to capture some quick data into the live stream view (which was a feature that was already there prior to 17.3). And after clicking the “stop session” menu item, I will see the following.
Note that the “QuickSessionStandard” event session now has a “Stop” icon instead of a “play” icon. So yay – I was able to start and stop a session quickly from XE Profiler. In addition, XE profiler launched a live stream view just like we saw earlier when creating the same session from the template in the XE GUI. Now for a pro-tip – start and stop an XE Session from the old GUI – “right click any event session and select start/stop from the context menu.”
Yes it is that easy. In addition, only the available option for that session will be enabled (e.g. you cannot stop a session that is already stopped – or not running). In fact you can even start/stop from TSQL. If you try to stop a session that is not running in TSQL, you will get a warning message that it is already stopped. Far more intuitive than XE Profiler. You will get no indication that the session is unable to be stopped if it is already stopped. Let’s take a look at the old way.
And after the session is started, I can also quickly stop it.
You can also see from each of those images, that I have the option to watch live data for the session. Another easy access feature from the old XE GUI.
While XE Profiler has added an additional means to be able to start/stop sessions quickly, the fact of the matter is that it is not a new feature brought to the table by XE Profiler. All it did was add a different way of doing it. I will also add that this new method can actually be somewhat confusing as well. You can only determine (visually) if the session is running or stopped by expanding the “Extended Events” node. Stopping a session from the XE Profiler node does not close the livestream viewer so you could easily presume it is still running. The XE Profiler node gives you no insight into the actual state of the session.
And for giggles, this is how easy it is to start or stop a session via TSQL.
ALTER EVENT SESSION QuickSessionStandard on SERVER
STATE = START;
ALTER EVENT SESSION QuickSessionStandard on SERVER
STATE = STOP;
If I run the statement to stop the session when it is already stopped, I will get the following:
Msg 25704, Level 16, State 1, Line 9
The event session has already been stopped.
I have previously covered this specific topic (start/stop sessions) in my 60 Day series which can be found here.
Customizable XE Profiler Sessions
Let’s take a gander at the previous section where I showed the context menu available in XE Profiler and not the extent of that menu. The profiler iteself does not offer any sort of customization. You have only two default sessions. You cannot change either session within that particular feature.
Since I cannot customize anything for these sessions via the XE Profiler, let’s use the XE GUI that is tried and true. I will effectively perform the following via the XE Session Properties window:
ALTER EVENT SESSION [QuickSessionStandard] ON SERVER
DROP EVENT sqlserver.attention, DROP EVENT sqlserver.logout
And after I am done, that session will look like the following:
CREATE EVENT SESSION [QuickSessionStandard] ON SERVER
ADD EVENT sqlserver.existing_connection(SET collect_options_text=(1)
ADD EVENT sqlserver.login(SET collect_options_text=(1)
ADD EVENT sqlserver.rpc_completed(
ADD EVENT sqlserver.sql_batch_completed(
ADD EVENT sqlserver.sql_batch_starting(
WITH (MAX_MEMORY=8192 KB,EVENT_RETENTION_MODE=ALLOW_SINGLE_EVENT_LOSS,MAX_DISPATCH_LATENCY=5 SECONDS,MAX_EVENT_SIZE=0 KB,MEMORY_PARTITION_MODE=PER_CPU,TRACK_CAUSALITY=ON,STARTUP_STATE=OFF)
And visually, from the GUI, it will look like this:
You can see that the aforementioned events are definitely gone from this session. From here, I can absolutely start that session from the XE GUI and it will run just fine. I can hit “watch live data” from the context menu and it will open up the previous view of the live data that was used (so the exact same configuration of that window because the XE GUI has always done that). If I double check my session after it is started, I will be able to confirm that the altered session is indeed still tact just the same as I customized it.
Let’s go ahead and stop that and then “launch” it from the XE Profiler now. After the “launch” I will re-script the session to verify that it is either the same or altered from what I had configured. In this case, since the session was already in place, I will find that the XE Profiler did not alter my session in any way and merely started the session. That is a win for XE Profiler in that it was able to determine that the session did indeed exist. However, I have to use the XE GUI and not XE Profiler in order to get a decent config on those default sessions.
XE Profiler only has SQL Profiler Events
This is actually an interesting statement. While the XE Profiler relies on templates based on SQL Profiler and the events in those templates are events that are available in SQL Profiler, they are not exclusive to SQL Profiler. These events can be used in Extended Events and have been a part of the XE Engine since inception. So, I would call this one fiction as well. I think an obvious litmus test for that is that the events are actually running through an XE Session so they must obviously be XE events as well.
Up to this point I have not addressed any changes in the Extended Events Profiler that were made for SSMS 17.4. Here is where it seems we compound a bit of confusion for the masses. Not only do we have this Extended Events tool that we have decided to call “Profiler” which has already had many people asking me about it because the name confused them (is it profiler or is it XE??), but it seems that the identity crisis for this feature is exacerbated slightly with a sudden name change.
Using yet another very clean install of SSMS on a different instance of SQL Server to ensure that none of the XE Profiler components had been used or any of the default sessions created and launched, I have the following:
Yes, the name change is very innocuous but it can lead to some confusion for various parties involved. If a set of step by step instructions says to do something and the learner cannot find that explicit node, they will become confused.
For anybody that has been working with XE for some time, they will know that XE is synonymous with XEvent and will quickly figure it out.
So, in wrapping up this very long article, I want to recap the score of the Fact v. Fiction items. The final tally is Fact 1 and Fiction 9 (9 original list items plus 1 bonus entry). This means that there is a whole lot of stuff going on around out there about this new feature that is just not accurate. While some may be able to derive some small use from the XE Profiler, it really does not add anything that you could not already do with either TSQL or the old XE GUI.
Some say this is a way of bridging the gap. In my opinion, that gap was already bridged with the GUI that has been available for several years. Some say that maybe this tool needs to integrate a way to shred XML faster. To that, I say there are methods already available for that such as Powershell, the live data viewer, the Target Data viewer, or even my tools I have provided in the 60 day series.
I would challenge those that are still unfamiliar with the XE GUI (out for nearly 6 years now) to go and read some of my articles or articles by Jonathan Kehayias about the power that is in XE as well as some of the power in the GUI.