Can't create Raw Reflection


I’m getting Failure getting source [__accelerator]. error when trying to create a Raw Reflection of Delta table.

Does anyone know how to fix this?


Hello @asoderznik,

Could you please provide the profile for this failed raw reflection query?. You can “download profile” and attach it here.

Hi @Basapuram_Kumar ,

thanks for the reply. Here is the downloaded profile: (24,4 KB)

In the raw profile tab, there is an error sub-tab that includes the stack trace. It says: Access Denied (Service: Amazon S3; Status Code: 403; Error Code: AccessDenied;

The referenced source __accelerator is the S3 location specified in path.dist. This is the distributed file system where the accelerations (i.e. reflection materializations) are written to and shared among the executors.

@asoderznik Try below steps

  • Restart and see if that fixes the issue
  • To get to the RCA of why this happened
  • Log on to
  • ps -ef | grep dremio
  • Get the server.log on the date it was last restarted,
  • There will be a section where the plugins like __accelerator will be loaded and marked “Healthy” or “Pending” or “Unavailable”, if not “Healthy” there should a reason mentioned

Also if you have AWS support give them the extension ID printed in the error message and that will tell you the exact reason