VDS cannot config Reflection Refresh

Hi Team,

There is no “Reflection Refresh” for a VDS, but seems it would refresh hourly. Two questions

  1. How to config it
  2. How to trigger it manually (via API)?
  3. What’s the retention strategy for the accelerator history?
  4. We enable the reflection on PDS, and create a VDS on top of it. When we query the VDS, the reflection does not use. Why?

Hi @popejune

  1. The refresh policy is based on the PDS inside the VDS. You can also query sys.reflection_dependencies to see the link between your reflection and all its parent/grandparent datasets.
  2. Here’s the REST API. Dremio Remember, this is on the PDS and not the VDS that anchors your reflection.
  3. This will depend on whether your reflection is full or incremental. But you can check sys.materializations to see every refresh job that is run for a reflection. This property controls how long until we physically deleted deprecated materializations: reflection.deletion.grace_seconds
  4. You can enable planner.verbose_profile which gives you an acceleration tab in the profile and you can try to trouble shoot from there. If you give me a verbose profile, I can take a look too.