Fabric Notebook disconnects when running a certain code cell

This looks like a session-level failure that happens before your code even starts running — usually tied to Spark kernel startup or resource allocation issues.

Here’s what might be causing it and what you can try:

1. Session Timeout or Idle Expiry
   If the notebook was idle for a while, the session might have expired silently. Try restarting the notebook kernel and re-running the cell immediately.

2. Spark Pool Resource Limits
   Even if your colleague increased the pool size, check if:

   • The max concurrency is being hit (too many notebooks using the same pool)
   • The session quota per user is exceeded

3. Code Cell Content
   If the cell has heavy operations (e.g. large joins, wide transformations), try:

   • Breaking it into smaller steps
   • Caching intermediate results
   • Logging the Spark plan (df.explain())

4. Plugin State: Cleanup
   This usually means the session failed during init and Fabric is cleaning up. It could be a transient backend issue — try running the same cell in a new notebook or after a short wait.

5. Diagnostics
   Since you don’t have admin rights, ask your admin to check:

   • Spark job logs in the Fabric Admin portal
   • Capacity metrics around the time of failure

Let me know if you want help reviewing the code in that cell — sometimes a small tweak can avoid triggering these session-level errors.

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