Editing notebooks is extremely slow in the browser

[x_mark_x]

Hello there Fabricators!

I have an annoying issue when working with Notebooks in Fabric, namely that when I click on the code in a cell, there is a huge lag between the click and when the cursor appears in the code, or when i start to type, the letters appear much later than my input.
This lag can sometime even be 10 seconds!

This is not only annoying but can make editing of the code almost impossible at times.

This issue is present since i started to use Fabric.
I tried to minimize the number of open tabs in my broswer, but it does not seem to effect the performance.
Opening or interacting with other websites is as fast as expected, it is only the Fabric Notebooks that has this input lag.

Did anybody else face this issue, and if yes did you find any solutions to how this input lag can be minimized?

Thank you for your insights in advance!

[v-veshwara-msft · Accepted solution]

Hi @x_mark_x ,

Thank you for reaching out to the Fabric Community.

Based on your description, the lag may be influenced by factors such as notebook size, the number of imports, and resource utilization. Fabric Notebooks have certain limitations that might be relevant to your scenario:

• A maximum of 256 code cells can be executed in a single notebook.

• Notebook content size is limited to 32 MB.
• The upper limit for notebook activities or concurrent notebooks in notebookutils.notebook.runMultiple() is 50.

• The longest possible running job time is 7 days.

Please refer this link for more details: Fabric Notebook known limitation - Microsoft Fabric | Microsoft Learn

Since you are working with long notebooks and importing multiple functions, as you mentioned, dividing your notebook into smaller sections based on each wrangler/transformation object and limiting imports to only the necessary functions are great steps toward optimizing performance

Here is a similar thread: Solved: Notebook – input/keypress lagging when writing in ... - Microsoft Fabric Community

Please share any insights after testing these changes, and let us know if you need further assistance.

If this helps, kindly consider accepting it as the solution to assist other community members, and a kudos would be appreciated.

Thank you!

Best regards,
Vinay.
Microsoft Fabric Community Support.

[concreterLiam · Accepted solution]

---

@x_mark_x wrote:

Hello there Fabricators!

I have an annoying issue when working with Notebooks in Fabric, namely that when I click on the code in a cell, there is a huge lag between the click and when the cursor appears in the code, or when i start to type, the letters appear much later than my input.
This lag can sometime even be 10 seconds!

This is not only annoying but can make editing of the code almost impossible at times.

This issue is present since i started to use Fabric.
I tried to minimize the number of open tabs in my broswer, but it does not seem to effect the performance.
Opening or interacting with other websites is as fast as expected, it is only the Fabric Notebooks that has this input lag.

Did anybody else face this issue, and if yes did you find any solutions to how this input lag can be minimized?

Thank you for your insights in advance!

---

Have you tried clearing your browser’s cache? That can help with performance sometimes, especially with apps like Fabric that store data. Another thing you could try is switching browsers. Sometimes Chrome or Firefox can handle things a little differently, and that could make a difference. Also, check if any browser extensions are slowing things down, Some of them, especially ones for security or ad-blocking, can have a big impact on performance.

If you haven’t already, make sure both your browser and Fabric are up to date, as they often release updates that improve things like performance. Lastly, maybe try working in an incognito window or close out some background processes to reduce the load on your browser.

[concreterLiam · Accepted solution]

---

@x_mark_x wrote:

Hello there Fabricators!

I have an annoying issue when working with Notebooks in Fabric, namely that when I click on the code in a cell, there is a huge lag between the click and when the cursor appears in the code, or when i start to type, the letters appear much later than my input.
This lag can sometime even be 10 seconds!

This is not only annoying but can make editing of the code almost impossible at times.

This issue is present since i started to use Fabric.
I tried to minimize the number of open tabs in my broswer, but it does not seem to effect the performance.
Opening or interacting with other websites is as fast as expected, it is only the Fabric Notebooks that has this input lag.

Did anybody else face this issue, and if yes did you find any solutions to how this input lag can be minimized?

Thank you for your insights in advance!

---

Have you tried clearing your browser’s cache? That can help with performance sometimes, especially with apps like Fabric that store data. Another thing you could try is switching browsers. Sometimes Chrome or Firefox can handle things a little differently, and that could make a difference. Also, check if any browser extensions are slowing things down, Some of them, especially ones for security or ad-blocking, can have a big impact on performance.

If you haven’t already, make sure both your browser and Fabric are up to date, as they often release updates that improve things like performance. Lastly, maybe try working in an incognito window or close out some background processes to reduce the load on your browser.

[x_mark_x]

Thank you for your feedback @concreterLiam,

feels like there are a couple of things i can try now thanks to your, @mhseko and @v-veshwara-msft advises.
As I wrote before, I will try out these recommendation when i will be between projects and leave a feedback on how these have effected the performance in the browser.

[v-veshwara-msft]

Hi @x_mark_x ,
We haven't heard back from you since our last reply and wanted to check if you had a chance to test the notebook performance after applying the suggested optimizations. If you have, please share your feedback here to help others facing similar issues.
If any of the responses were helpful, kindly consider marking them as "Accepted Solutions" to assist others in finding the solution more easily.
If you still need further assistance, feel free to reach out.
Thank you.

[x_mark_x · Accepted solution]

Hi @v-veshwara-msft,

I didn't forget this thread, but i had little time to test all the suggested solutions, plus i worked a little less in notebooks the last month.

When i noticed a slow response time in the notebooks in the browser, i firstly tried to get rid of all the cells where i had unnecessary code. I often experiment with different transformations in a separate notebook to be able to try out and test the validity of the transformations, and this notebook is always the longest. 

When i got rid of the unneccesary code, i (subjectively) experienced a faster response time within the notebook.

Also after restarting the computer or the browser i often experienced a little faster response time, which degraded over time, so my gut feeling tells me that @concreterLiam's suggestion about clearing the cache in the browser might have positive effects, i still need to test this more thoroughly.

As said before, i will get back with more information when i had the time to test the other suggestions, but so far smaller notebooks seems to do the trick.

[v-veshwara-msft]

Hi @x_mark_x ,

Just following up again to check if you've had a chance to try any of the remaining suggestions, such as clearing your browser cache or reducing the number of imports.

If you've seen any other changes or need additional help, feel free to let us know. Your feedback could be valuable to others facing similar issues.

If any of the previous replies addressed your concern, please consider marking them as "Accepted Solutions" to help guide the community.

Thank you.

[v-veshwara-msft]

Hi @x_mark_x ,

Thank you again for your update. Just checking in to see if you’ve had a chance to test any of the other suggestions, such as clearing the browser cache or limiting the number of imports.

It’s good to hear that reducing notebook size has helped improve responsiveness. If you've observed any further changes or need continued support, feel free to share your experience. Your input could help others facing similar issues.

Meanwhile, if any of the responses helped address your concern, marking them as "Accepted Solutions" would assist other community members in finding useful answers more efficiently.

Best regards,

Vinay.

[concreterLiam]

---

@x_mark_x wrote:

Thank you for your feedback @concreterLiam,

feels like there are a couple of things i can try now thanks to your, @mhseko and @v-veshwara-msft advises.
As I wrote before, I will try out these recommendation when i will be between projects and leave a feedback on how these have effected the performance in the browser.

---

You're very welcome! I'm glad the suggestions were helpful. Definitely take your time to test them out when you can. I’ll be interested to hear how things improve after you try them. If you run into any other issues or have more questions down the line, feel free to reach out! Good luck with your projects! 😊

[v-veshwara-msft]

Hi @x_mark_x ,

Thank you for the follow-up! Glad to hear that the suggestions were helpful, and it's great that you’re planning to try them out when you’re between projects. We’d really appreciate any feedback once you’ve had a chance to test how these changes affect performance in your browser. Your insights could be valuable for others facing similar challenges.

Also, thank you @mhseko  for sharing your experience and mentioning the improvements announced during the Fabric conference. Yes, Microsoft is actively working on enhancing notebook performance and responsiveness based on user feedback. We’re glad to hear you’ve noticed better performance already.

If any of the replies helped address your issue, please consider marking it as the "Accepted solution" to help others in the community find answers more quickly.

Best regards,
Vinay

Community Support.

[mhseko]

I caught wind at the fabric conference that MS has been working on improving this.  I am unsure about the timing of the release, but if I recall correctly, it has been released.  So far, it seems to be performing better for me.  

[v-veshwara-msft · Accepted solution]

Hi @x_mark_x ,

Thank you for reaching out to the Fabric Community.

Based on your description, the lag may be influenced by factors such as notebook size, the number of imports, and resource utilization. Fabric Notebooks have certain limitations that might be relevant to your scenario:

• A maximum of 256 code cells can be executed in a single notebook.

• Notebook content size is limited to 32 MB.
• The upper limit for notebook activities or concurrent notebooks in notebookutils.notebook.runMultiple() is 50.

• The longest possible running job time is 7 days.

Please refer this link for more details: Fabric Notebook known limitation - Microsoft Fabric | Microsoft Learn

Since you are working with long notebooks and importing multiple functions, as you mentioned, dividing your notebook into smaller sections based on each wrangler/transformation object and limiting imports to only the necessary functions are great steps toward optimizing performance

Here is a similar thread: Solved: Notebook – input/keypress lagging when writing in ... - Microsoft Fabric Community

Please share any insights after testing these changes, and let us know if you need further assistance.

If this helps, kindly consider accepting it as the solution to assist other community members, and a kudos would be appreciated.

Thank you!

Best regards,
Vinay.
Microsoft Fabric Community Support.

[mhseko]

I have had similar troubles over the recent months.  Those delays are more than tripling my time to develop.  I have tried different browsers to no avail.  I haven't been able to pinpoint a commonality when the issues arise.  Sometimes it seems due to notebooks that have many lines.  Other times it seems to occur when I use runmultpiple util.  

[x_mark_x]

Thanks for your input mhseko!

I am indeed working with rather long notebooks plus i import all the functions from pyspark.sql.types/functions and window.

My gut feeling says that these could affect the notebook performance, so thank you again for the input.

I will try and divide it up into several notebooks for each wrangler / transformation object i have and also try to import only the functions i actually use in my code.
I will leave a feedback if it helped with the lag when my time allows it.