Cannot recover from long-running formula

[samkhal]

I have a formula which is taking a long time to run. It's running on a table of 1k rows and the formula is

col_ids = [col.col_id for col in table.table.all_columns.values() if not col.col_id.startswith("gristHelper_")]
return '\n'.join(col_ids)

Initially, I just saw the "still working" dialog. Now I seem to be in an unresponsive state for 20 minutes:

• Opening the document presents a blank page with just the top menu bar visible.
• I already has a snapshot open in another tab. Everything seems functional there (and I exported it just in case), except that the Snapshots sidebar is empty and displays "Snapshots are unavailable" after some time. Console:

  ERROR: TypeError: NetworkError when attempting to fetch resource. [errors.ts:94:2](https://grist-static.com/v/263dea7ee/core/app/client/models/errors.ts)
  S errors.ts:94
  _buildSnapshots DocHistory.ts:77

• Console output when opening the document:

  Comm.useDocConnection(redacted): useCount now 1 [Comm.ts:165:4](https://grist-static.com/v/redacted/core/app/client/components/Comm.ts)
  Comm request #0 openDoc 
  Array(3) [ "redacted", "default", undefined ]
  [Comm.ts:262:4](https://grist-static.com/v/redacted/core/app/client/components/Comm.ts)
  GristWSConnection.send[false] {"reqId":0,"method":"openDoc","args":["redacted","default",null]} [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection: onopen: Connected [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection: onmessage (311 bytes) [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection established: clientId fb9618fb85b35cd5 counter 1 needReload false [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection.send[true] {"reqId":0,"method":"openDoc","args":["redacted","default",null]} [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  Comm: Triggering event clientConnect [Comm.ts:375:8](https://grist-static.com/v/redacted/core/app/client/components/Comm.ts)
  App clientConnect event: needReload false version redacted [App.ts:140:14](https://grist-static.com/v/redacted/core/app/client/ui/App.ts)
  GristWSConnection: onmessage (322 bytes) [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection skipping duplicate 'clientConnect' message [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection.send[true] {"beat":"alive","url":"https://docs.getgrist.com/x9QjeLNLxoqc/Transactions","docId":"redacted"} [GristWSConnection.ts:99:12](https://grist-static.com/v/redacted/core/app/client/components/GristWSConnection.ts)
  GristWSConnection.send[true] {"beat":"alive","url":"https://docs.getgrist.com/x9QjeLNLxoqc/Transactions","docId":"redacted"} [GristWSConnection.ts:99:12](https://grist-static.com/v/263dea7ee/core/app/client/components/GristWSConnection.ts)

[dsagal]

There is a somewhat hidden way to recover from a data engine that's in an infinite loop. Go to document "Settings" page (in the bottom right of the left panel), and find the Engine setting there:

Click the ☠️ icon. It kills the data engine, and causes the document to reload. You should see the version before your change that introduced the infinite loop.

[samkhal]

10 hours later, still broken. I cannot access document settings; the page looks like this:

I can access the sidebar from within an earlier snapshot. If I click the skull, the page reloads with a message: "Too many backlogged requests for document"

[dsagal]

OK, apologies. It looks like the document got into a bad state while getting closed. I think there is a genuine bug that allows an infinite loop to interfere with shutdown. We shut down the data engine forcibly on the server side, so if you re-open it, it should work again.

If you are still having trouble, could you please share access to the document with support@getgrist.com? (You can find instructions for how to share from the docs homepage without having to open it at https://support.getgrist.com/sharing/.)

[samkhal]

The document works again for me.