SQL Server Profiler is depecrated

The SQL Server Profiler has been around for a very long time. It is very useful if you are trying to see in real time what SQL queries are being executed against your database. However, in the SQL Server 2016, Microsoft announced that the SQL Profiler will be deprecated in future versions.

Does this mean that there are no profiling options left in SQL Server? Luckily no, the SQL Profiler will be replaced by Extended Events(XE). Extended Events works via Event Tracing (ETW) which consumes less resources and allows much more flexibility. It also can monitor more events than the Profiler.

Where can I find these Extended Events?

Open SQL Server Management Studio( for SQL 2014 or higher) and connect to one of your Database instances
Go to Management>Extended Events:

Expand the Extended Events section, right click on Sessions and choose New Session Wizard

The Session wizard will help us to select the events we want to profile. Click on Next >

Specify a session name and click Next >

Now you can choose an existing template. Leave the Do not use a template radiobutton checked and click on Next >

The next screen is where the real work is done. Here you specify the events you want to monitor. Luckily you can search through them. Select some events you want to track and click Next >

Now you can specify any global fields(e.g. username, database name,…) you want to capture together with the events. Click Next > to continue

Next step is to apply some optional filters to limit the amount of data that is returned. Click Next > to continue

The session storage allows you to specify how to collect the data and store it. Click Next >.

On the Summary you get an overview of the selected options. Click Finish to generate the Session.

Note: There is an option to generate a script from this configuration. So you can re-use it later.

After clicking Finish you end up on a Success page. Here you can start the session immediately and watch the data when it is captured.

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME ...

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...

A complex system designed from scratch never works

A few years ago, I worked as an architect on a big mainframe rewrite. I still count it as one of my failures. Not because the technology was wrong, but because I couldn't convince the management team to simplify the approach. Years later, the organization is still struggling to get the new system up and running. I left the project at the time, because I couldn't put my name behind an approach that would take very long and cost a lot of money without a working system to show for it along the way. Gall’s Law That memory keeps coming back to me, because it's a textbook case of Gall's Law playing out in real life. Gall's Law , from John Gall's Systemantics , states it plainly: A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works, and it cannot be patched to make it work. You have to start over with a simple system that works. What does that mean in practice,...

The art of simplicity

Search This Blog