What is the basis for setting up Reflections?
On what basis we decide that a column need to be added to aggregate reflections?
Lets say, if a table has following columns:
ID
Date
Dimension
Measure
Which of these should be tagged in aggregate reflections?
How a row reflection is different from aggregate reflection?
Hi, this tutorial may be helpful: https://www.dremio.com/tutorials/getting-started-with-data-reflections/
Dremio can only accelerate columns that are included in a reflection.
Raw reflections are for ad-hoc queries that return individual rows.
Aggregation queries are for group by and aggregation queries.
Each type of reflection can accelerate different kinds of query patterns.
You can also have multiple reflections on a dataset. For example, it may make sense to partition the data by date for one set of query patterns, and by customer_id for a different set of query patterns.
Hope that helps.