Reflection related

1

Experts,

I can see below details in a job related to view

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I am new to dremio and need your to understand below:

  1. Is it indicating that the view utilizes the reflection feature enabled on the ‘tbExtractContract’ table?
  2. Can you explain the significance of the details presented in the “Reflection Used” and “Reflection Not Used” sections? Does it imply a breakdown of views where the reflection is actively employed and views where it is not utilized? Please provide further clarification.
  3. In the entire logic of the view, which is the context for my reference to these job details, I couldn’t find any object listed in the ‘Reflection Used’ and ‘Reflection Not Used’ sections. I’m curious about why those object names are appearing in the job details.

Thanks,
Rajneesh

2
  1. Yes. Your query scanned the table tbExtractContract and it was accelerated by the raw reflection on said table.
  2. Reflection Used means that the cost based optimizer picked the reflection and used it in the query plan. Reflection Not Used means that the reflection was not picked due to cost or that the reflection did not match into the query. For example, if your scan on the table needed a column that the reflection did not materialize.
  3. Your queries don’t need to reference reflections directly. Dremio’s planner will match reflections into the query based on overlapping tables and views automatically. These details are available in the raw profile’s acceleration tab.
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Thanks, it helps. I appreciate your input.