feat(event): Add view to allow caching of charge/filters for billable…

…_metrics (#2231)

This PR is part of the real-time aggregation epic

This PR adds a new `billable_metrics_grouped_charges` database view. It
selects the charges for each organization/billable metric code/plan
tupple. It will be used to route events received on the ingest service
to the right bucket in order to perform a pre-computation and allow
future "real time aggregation"

app/models/charge_filter.rb

@@ -5,7 +5,7 @@ class ChargeFilter < ApplicationRecord
   include Discard::Model
   self.discard_column = :deleted_at
 
-  belongs_to :charge, -> { with_discarded }
+  belongs_to :charge, -> { with_discarded }, touch: true
 
   has_many :values, class_name: 'ChargeFilterValue', dependent: :destroy
   has_many :billable_metric_filters, through: :values

db/migrate/20240701083355_create_billable_metrics_grouped_charges.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class CreateBillableMetricsGroupedCharges < ActiveRecord::Migration[7.1]
+  disable_ddl_transaction!
+
+  def change
+    create_view :billable_metrics_grouped_charges
+  end
+end

db/views/billable_metrics_grouped_charges_v01.sql

@@ -0,0 +1,42 @@
+select
+    billable_metrics.organization_id,
+    billable_metrics.code,
+    billable_metrics.aggregation_type,
+    billable_metrics.field_name,
+    charges.plan_id,
+    charges.id as charge_id,
+    charge_filters.id as charge_filter_id,
+    json_object_agg(
+        billable_metric_filters.key,
+        coalesce(charge_filter_values.values, '{}')
+        order by billable_metric_filters.key asc
+    ) FILTER (WHERE billable_metric_filters.key IS NOT NULL) AS filters,
+    (
+        case when charges.charge_model = 0 -- Standard
+        then
+            coalesce(charge_filters.properties->'grouped_by', charges.properties->'grouped_by')
+        else
+            null
+        end
+    ) AS grouped_by
+
+from billable_metrics
+    inner join charges on charges.billable_metric_id = billable_metrics.id
+    left join charge_filters on charge_filters.charge_id = charges.id
+    left join charge_filter_values on charge_filter_values.charge_filter_id = charge_filters.id
+    left join billable_metric_filters on charge_filter_values.billable_metric_filter_id = billable_metric_filters.id
+where
+    billable_metrics.deleted_at is null
+    and charges.deleted_at is null
+    and charges.pay_in_advance = false
+    and charge_filters.deleted_at is null
+    and charge_filter_values.deleted_at is null
+    and billable_metric_filters.deleted_at is null
+group by
+    billable_metrics.organization_id,
+    billable_metrics.code,
+    billable_metrics.aggregation_type,
+    billable_metrics.field_name,
+    charges.plan_id,
+    charges.id,
+    charge_filters.id