Parallel Pool Job Stuck on “Job Queued” for 10–15 Minutes Before Connecting

Hello,

I’m experiencing a delay issue when starting a parallel pool in MATLAB. Whenever I run code that uses parfor or opens a parallel pool, MATLAB prints repeated messages like:

25-Nov-2025 09:12:11: Job Queued. Waiting for parallel pool job with ID 5 to start ...

25-Nov-2025 09:13:12: Job Queued. Waiting for parallel pool job with ID 5 to start ...

25-Nov-2025 09:14:13: Job Queued. Waiting for parallel pool job with ID 5 to start ...

This continues for about 10–15 minutes before the pool finally connects. After it connects, everything runs normally — the problem is only the long waiting time before the workers start.

I’m looking for a fix or configuration change that eliminates this long delay and allows the pool to start right away.

[Walter Roberson]

Are you using Distributed Computing, or is this a normal local parallel process pool?

[Ahmed]

its a normal local parallel process pool

[jessupj]

same ongoing problems here on R2025a and R2025b.

[Raymond Norris]

@jessupj can you try a threaded pool?

[jessupj]

Use of class or function matlab.system.internal.executeCommand is not supported on a thread-based worker. Use a PARPOOL('Processes') process-based pool or a different process-based pool instead.

Answer 1

[Raymond Norris]

You might consider using the Threaded profile. It ought to start quicker and might support the features you need for your parfor.

Alternatively, contact MathWorks Technical Support ([e-mail]) to resolve this.