[Feature request] Use dimensions from pre-aggregations to calculate measures

[itestyoy]

Hi there!

We’re trying to build a cube like the one below, and we expected it to use pre-aggregations to calculate the metric because the pre_aggregations include the day dimension. However, the generated query doesn’t seem to involve the pre-aggregations.

Feature Request: Use dimensions from pre-aggregations to calculate measures.

cube('model', {
  public: false,
  title: 'model',

  sql: `SELECT 1 as metric, 1 as day`,

  dimensions: {
    day: {
      sql: `day`,
      type: 'number'
    }
  },

  measures: {
    metric: {
      sql: `${day}`,
      type: `count_distinct`
    }
  },

  pre_aggregations: {
    model_rollup: {
      measures: [],
      dimensions: [
        CUBE.day
      ],
      external: false,
    }
  }
});

[paveltiunov]

@itestyoy If you're trying to get an additive rollup here I think count_distinct_approx would be your best shot. While doing count distincts on the Cube Store side is definitely possible it isn't that scalable as it ultimately leads to raw data extraction.