CPU consumption spikes

[fontaine-chris]

Development environment where the bug occurred

• Db2 Developer Extension version: 2.2.4
• Editor platform
  • Visual Studio Code
  • Editor platform version: 1.104.1 and 1.104.3
• Operating system on which your editor runs (for example, Windows 10 2004 or MacOS Catalina 10.15.7): Windows 11
• Java Version (Run java -version and paste the details here): 21
• Db2 for z/OS version (including function level for Db2 12): 13 M505
• Log files attached?: No

Problem description

Detailed steps for reproducing the problem:

The CPU seems to occasionally spike on the workstation when VS Code is open even when nothing is being executed currently. This causes the workstation to become nearly unresponsive. The IBM Semeru Runtime binary associated with the developer extension takes the most CPU. The workstation is has 32 GB Ram and an Intel Core Ultra 7 265H 2.2 Ghz. This happened on more than one workstation with the same configuration. Closing all open tabs prior to closing VS Code seems to alleviate the problem. This does not happen on every workstation or for every user.

[Anshul-17535]

Hi @fontaine-chris ,
Thank you for sharing the detailed description and environment information
According to your description the behavior appears to be related to background activity from the Db2 Developer Extension

To help us narrow down the root cause can you help us with some diagnostics :

1. Please enable debug logging for the extension. When the CPU spike occurs while editors are idle, check whether debug logs are still being generated if possible, share the relevant log files captured.
2. When the system becomes unresponsive, from your control manager. Sort processes by CPU usage Take screenshots showing:
   the Java / IBM Semeru Runtime process consuming CPU it's percentage and process details (Please detail view if available)
3. Also once confirm when spike occurs just disable the developer extension to confirm the CPU usage drops instantly

This information will help us determine whether the issue is related to Java background processing, extension lifecycle cleanup, or editor state, and allow us to move forward with a targeted fix.

We will be checking from our side simultaneously and will keep you updated as we progress with the investigation.
Thanks & Regards,
Anshul

[fontaine-chris]

Log and Screen Shots CPU Consumption DB2 Developer Extension.docx

Here is a doc file containing the log and screen shots. If you want something more, please let me know.

[Anshul-17535]

Hi @fontaine-chris ,

Thanks for sharing the logs — they were very helpful.
For safety, please save any open work before proceeding. And follow these steps

Force-quit the current VS Code process
Use Task Manager (Windows) or Activity Monitor (macOS)
Restart VS Code
Open the extension settings
Go to Settings -> open the extension settings
Search for Telemetry Level
Check the telemetry setting
If telemetry is already set to Off, please let us know
If not, please set it to Off

After this, keep using VS Code and when done keep it open in an idle state and check whether the CPU spike still occuring.
Thanks again for your help — please let us know the results, and we’ll continue digging into this.

Thanks & regards,
Anshul

[fontaine-chris]

The change was made to turn off telemetry, but this did not resolve the issue.

[Anshul-17535]

Hi @fontaine-chris,

To help us further narrow down where the CPU usage is originating from, could you please help clarify the following

When the CPU usage spikes, does it drop only after closing the editors, or only after disabling the Db2 Developer Extension
If VS Code is kept idle does the CPU spike continue, or does it eventually settle on its own?

When the extension is idle before the spike occurs, are there any specific debug-level logs being printed?
After the spike starts, do debug logs continue to be generated while VS Code remains idle?
in both cases can you attach the debug logs for us to examine further

Do you recall whether the CPU spike tends to occur after any specific action, such as connecting to a Db2 connection, running a SQL statement, or any other similar operation?

Thanks & regards,
Anshul

[fontaine-chris]

The people most affected by this issue have not been available for further analysis. The temporary solution has allowed them to continue working. I will update this issue when we are able to collect more data.