topic Re: Starting Session takes really slow - notebook session Microsoft Fabric in Data Engineering

Starting Session takes really slow - notebook session Microsoft Fabric

naanii — Wed, 29 May 2024 06:56:15 GMT

Hi Community,

I have a question regarding starting sessions (New standard session and New high concurrency session) for running notebooks in Microsoft Fabric. We are running an F64 trial license (Runtime versionRuntime 1.2 (Spark 3.4, Delta 2.4)).

When I start a session, it takes 3 minutes.
When my colleague starts a session, it takes 3 seconds.

What is the cause of this difference? And what changes do I have to make to get a 3 second boot time?

Please let me know if anyone can help me.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

egons11 — Wed, 29 May 2024 07:57:06 GMT

I have also been facing a similair issue recently, with slow spark cluster session starts, even though we are still running on F64 trial.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Anonymous — Wed, 29 May 2024 10:26:55 GMT

Hi @naanii , @egons11 ,

Thanks for using Fabric Community.
When I tried to check this issue, my session started in 5 sec.

Are you people still facing this issue?
Few factors can be - Network latency, Regional Differences, browser issues, or temporary Fabric service hiccups could also contribute to the delay.

Hope this is helpful. Please do let me know incase of further queries.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

egons11 — Wed, 29 May 2024 10:39:54 GMT

Now, it's actually better.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Anonymous — Thu, 30 May 2024 11:29:05 GMT

Hi @naanii ,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet.
Otherwise, will respond back with the more details and we will try to help .

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Anonymous — Fri, 31 May 2024 11:20:33 GMT

Re: Starting Session takes really slow - notebook session Microsoft Fabric

jwinchell40 — Fri, 31 May 2024 12:55:22 GMT

@naanii - One thing I've noticed is that when using the default Workspace settings for Notebooks it always starts up lightning fast. When I created a new default "Environment" to preinstall some libraries then it took longer to start-up the cluster. < 30s vs 2-3m. Not sure if that is relevant to your situation or not.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

O_Tarek — Tue, 04 Jun 2024 14:32:13 GMT

can confirm this is exactly what is happening to me as well

Re: Starting Session takes really slow - notebook session Microsoft Fabric

naanii — Mon, 17 Jun 2024 11:27:52 GMT

Hello,

I removed all the resources/items from My Workspace.

After creating a new notebook, I was able to start a session in about 5 sec.

Then I added a new Environment without any Libraries and this results in 3 minutes of starting time.

Why is this happing? We would like to import Libraries, but I think it is faster to import those in each of our notebooks instead of import those into a Environment.

Any ideas?

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Anonymous — Mon, 17 Jun 2024 12:56:10 GMT

Hi @naanii ,

Apologize for the issue you are facing. The best course of action is to open a support ticket and have our support team take a closer look at it.

Please reach out to our support team so they can do a more thorough investigation on why this it is happening: Link

After creating a Support ticket please provide the ticket number as it would help us to track for more information.

Hope this helps. Please let us know if you have any other queries.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

naanii — Tue, 18 Jun 2024 11:17:17 GMT

Hi,

Thanks for your reply.

Ticket number: 2406180050000408

Re: Starting Session takes really slow - notebook session Microsoft Fabric

theross — Wed, 26 Jun 2024 15:32:46 GMT

Was any solution/advice for this issue offered?

I'm seeing the exact same thing. A simple "Hello World" notebook using the default workspace environment will start a spark session in approx 4-5 seconds. Creating a new environment to add a custom library and setting it as the workspace default results in the same "Hello World" notebook now taking just over a minute to start a spark session.

This doesn't appear to be "Network latency, Regional Differences, browser issues, or temporary Fabric service hiccups..." as the difference in startup time can be reproduced with 100% reliability simply by switching the environment back and forth and re-running the same test notebook.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

theross — Wed, 03 Jul 2024 11:38:07 GMT

Raised support ticket: 2407030050003086

Will add to this thread once there's a response.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

theross — Wed, 03 Jul 2024 15:53:34 GMT

Spoke to one of the fantastic support people - sounds like it's unavoidable at the moment. Default environments are "ready to go", as soon as you create your own it takes time to spin them up.

Someone else has already submitted a request to improve this... hop on over and upvote if it'll help you: Microsoft Idea

Re: Starting Session takes really slow - notebook session Microsoft Fabric

tida — Thu, 22 Aug 2024 09:26:00 GMT

Hi all,

Since a couple of days it takes about 3min to start a session, where it previously was about 3sec!

I already switched to runtime 1.3 but the issue remains.

Location northern europe, trial version

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Richard_100 — Wed, 27 Nov 2024 15:42:27 GMT

We have this as well. Default envirnoment is very quick, but custom environments are very slow. It's quicker to %pip install all your stuff in the notebook rather than have it available to import from the envirnoment, which seems pretty mad to me.

Example:

Notebook with %pip install geopandas shapely pyproj fiona contextily, 11 seconds to start session and 28 seconds to run this first big import cell (installing and then importing all my libraries).

Notebook with in envirnoment with geopandas, shapely, pyproj, fiona and contextily installed there, and then import cell having the %pip part removed: 2 minutes to start session and then a further 20 seconds ish to run the cell.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Jeanxyz — Fri, 23 May 2025 08:31:52 GMT

Same issue here. I am opening a new notebook using default environment, the lakehouse I added to the notebook is quite small, only a few thousands of sample data with 6 columns. But it took 2 minutes to create a connection and even to print out a small table takes 14 seconds.

I read from newspaper that Microsoft has taken measures to control cost related to cloud computation. I'm wondering if that explains the slow speed I'm experience. Does anyone experience the same issue recently?

Re: Starting Session takes really slow - notebook session Microsoft Fabric

JonMozleyBtC — Fri, 23 May 2025 12:53:10 GMT

Just now I waited 16 mins for a session before giving up. Ironically the admin monitoring view lists this session as "Succeeded". I hope it didn't bill me any CUs. On the second attempt it only took 4 mins. The inconsistency is a bit concerning.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Jeanxyz — Sun, 25 May 2025 19:28:21 GMT

I realize my notebook is slow because I'm based in Europe, yet I'm using a capacity with US East region. After create a capacity in West Europe, the notebook becomes much faster.

Re: Starting Session takes really slow - notebook session Microsoft Fabric

Chris-Clark — Tue, 27 May 2025 15:35:14 GMT

I think my issue is the same. Even our default Environment now is like this. How do we go back/undo whatever happened?