feat: Use LowCardinality for smaller columns

models/base/schema.yml

@@ -18,7 +18,10 @@ models:
         description: "The xAPI object identifier"
       - name: course_id
         data_type: string
-        description: "The course identifier"
+        description: "The fully-qualified course identifier URL"
+      - name: course_key
+        data_type: String
+        description: "The course key for the course"
       - name: org
         data_type: string
         description: "The organization that the course belongs to"

models/base/xapi_events_all_parsed.sql

@@ -13,7 +13,7 @@
 
 select
     event_id as event_id,
-    JSON_VALUE(event::String, '$.verb.id') as verb_id,
+    toLowCardinality(JSON_VALUE(event::String, '$.verb.id')) as verb_id,
     COALESCE(
         NULLIF(JSON_VALUE(event::String, '$.actor.account.name'), ''),
         NULLIF(JSON_VALUE(event::String, '$.actor.mbox'), ''),
@@ -23,23 +23,32 @@ select
     -- If the contextActivities parent is a course, use that. It can be a "course"
     -- type, or a "cmi.interaction" type for multiple question problem submissions.
     -- Otherwise use the object id for the course id.
-    multiIf(
-        -- If the contextActivities parent is a course, use that
-        JSON_VALUE(
-            event::String, '$.context.contextActivities.parent[0].definition.type'
+    toLowCardinality(
+        multiIf(
+            -- If the contextActivities parent is a course, use that
+            JSON_VALUE(
+                event::String, '$.context.contextActivities.parent[0].definition.type'
+            )
+            = 'http://adlnet.gov/expapi/activities/course',
+            JSON_VALUE(event::String, '$.context.contextActivities.parent[0].id'),
+            -- Else if the contextActivities parent is a GroupActivity, it's a multi
+            -- question problem and we use the grouping id
+            JSON_VALUE(
+                event::String, '$.context.contextActivities.parent[0].objectType'
+            )
+            in ('Activity', 'GroupActivity'),
+            JSON_VALUE(event::String, '$.context.contextActivities.grouping[0].id'),
+            -- Otherwise use the object id
+            JSON_VALUE(event::String, '$.object.id')
         )
-        = 'http://adlnet.gov/expapi/activities/course',
-        JSON_VALUE(event::String, '$.context.contextActivities.parent[0].id'),
-        -- Else if the contextActivities parent is a GroupActivity, it's a multi
-        -- question problem and we use the grouping id
-        JSON_VALUE(event::String, '$.context.contextActivities.parent[0].objectType')
-        in ('Activity', 'GroupActivity'),
-        JSON_VALUE(event::String, '$.context.contextActivities.grouping[0].id'),
-        -- Otherwise use the object id
-        JSON_VALUE(event::String, '$.object.id')
     ) as course_id,
-    coalesce(
-        get_org_from_course_url(course_id), get_org_from_ccx_course_url(course_id), ''
+    toLowCardinality(splitByString('/', course_id)[-1]) as course_key,
+    toLowCardinality(
+        coalesce(
+            get_org_from_course_url(course_id),
+            get_org_from_ccx_course_url(course_id),
+            ''
+        )
     ) as org,
     emission_time as emission_time,
     event::String as event

models/completion/completion_events.sql

@@ -15,7 +15,7 @@ select
     CAST(emission_time, 'DateTime') as emission_time,
     actor_id,
     object_id,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     org,
     verb_id,
     JSON_VALUE(

models/enrollment/enrollment_events.sql

@@ -15,12 +15,14 @@ select
     cast(emission_time as DateTime) as emission_time,
     actor_id,
     object_id,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     org,
     verb_id,
-    JSON_VALUE(
-        event,
-        '$.object.definition.extensions."https://w3id.org/xapi/acrossx/extensions/type"'
+    toLowCardinality(
+        JSON_VALUE(
+            event,
+            '$.object.definition.extensions."https://w3id.org/xapi/acrossx/extensions/type"'
+        )
     ) as enrollment_mode
 from {{ ref("xapi_events_all_parsed") }}
 where

models/forum/forum_events.sql

@@ -14,7 +14,7 @@ select
     event_id,
     CAST(emission_time, 'DateTime') as emission_time,
     org,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     object_id,
     actor_id,
     verb_id

models/grading/grading_events.sql

@@ -16,7 +16,7 @@ select
     CAST(emission_time, 'DateTime') as emission_time,
     actor_id,
     object_id,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     org,
     verb_id,
     JSONExtractFloat(event, 'result', 'score', 'scaled') as scaled_score

models/instance/fact_instance_actors.sql

@@ -3,13 +3,13 @@
         materialized="materialized_view",
         schema=env_var("ASPECTS_XAPI_DATABASE", "xapi"),
         engine=get_engine("AggregatingMergeTree()"),
-        order_by="(emission_hour)",
-        partition_by="(toYYYYMM(emission_hour))",
+        order_by="(emission_day)",
+        partition_by="(toYYYYMM(emission_day))",
     )
 }}
 
 select
-    date_trunc('hour', emission_time) as emission_hour,
+    date_trunc('day', emission_time) as emission_day,
     uniqCombinedState(actor_id) as actors_cnt
 from {{ ref("xapi_events_all_parsed") }}
-group by emission_hour
+group by emission_day

models/instance/fact_instance_enrollments.sql

@@ -3,8 +3,8 @@
         materialized="materialized_view",
         schema=env_var("ASPECTS_XAPI_DATABASE", "xapi"),
         engine=get_engine("SummingMergeTree()"),
-        order_by="(emission_hour)",
-        partition_by="(toYYYYMM(emission_hour))",
+        order_by="(emission_day, course_key, enrollment_mode, enrollment_status)",
+        partition_by="(toYYYYMM(emission_day))",
     )
 }}
 
@@ -19,11 +19,10 @@ with
     )
 
 select
-    date_trunc('hour', emission_time) as emission_hour,
-    courses.course_name as course_name,
+    date_trunc('day', emission_time) as emission_day,
+    enrollments.course_key,
     enrollments.enrollment_mode as enrollment_mode,
     enrollments.enrollment_status as enrollment_status,
     count() as course_enrollment_mode_status_cnt
 from enrollments
-join {{ ref("course_names") }} courses on enrollments.course_key = courses.course_key
-group by emission_hour, course_name, enrollment_mode, enrollment_status
+group by emission_day, course_key, enrollment_mode, enrollment_status

models/instance/fact_instance_events.sql

@@ -3,13 +3,13 @@
         materialized="materialized_view",
         schema=env_var("ASPECTS_XAPI_DATABASE", "xapi"),
         engine=get_engine("AggregatingMergeTree()"),
-        order_by="(emission_hour)",
-        partition_by="(toYYYYMM(emission_hour))",
+        order_by="(emission_day)",
+        partition_by="(toYYYYMM(emission_day))",
     )
 }}
 
 select
-    date_trunc('hour', emission_time) as emission_hour,
+    date_trunc('day', emission_time) as emission_day,
     uniqCombinedState(event_id) as events_cnt
 from {{ ref("xapi_events_all_parsed") }}
-group by emission_hour
+group by emission_day

models/instance/schema.yml

@@ -14,32 +14,35 @@ models:
   - name: fact_instance_events
     description: "A materialized view summarizing site-wide xAPI event activity"
     columns:
-      - name: emission_hour
-        data_type: datetime(64)
-        description: "Time of summary, rounded to the nearest hour"
+      - name: emission_day
+        data_type: datetime
+        description: "Time of summary, truncated to the day"
       - name: events_cnt
         data_type: int
         description: "The number of xAPI events that occurred in the given hour"
 
   - name: fact_instance_actors
     description: "A materialized view summarizing site-wide user activity"
     columns:
-      - name: emission_hour
-        data_type: datetime(64)
-        description: "Time of summary, rounded to the nearest hour"
+      - name: emission_day
+        data_type: datetime
+        description: "Time of summary, truncated to the day"
       - name: actors_cnt
         data_type: int
         description: "The number of xAPI actors active in the given hour"
 
   - name: fact_instance_enrollments
     description: "A materialized view for summarizing site-wide enrollment activity"
     columns:
-      - name: emission_hour
-        data_type: datetime(64)
-        description: "Time of summary, rounded to the nearest hour"
+      - name: emission_day
+        data_type: datetime
+        description: "Time of summary, truncated to the day"
       - name: course_name
         data_type: String
         description: "The name of the course"
+      - name: course_key
+        data_type: String
+        description: "The course key for the course"
       - name: enrollment_mode
         data_type: string
         description: "The name of the enrollment mode (ex: audit, honor)"

models/navigation/navigation_events.sql

@@ -15,7 +15,7 @@ select
     cast(emission_time as DateTime) as emission_time,
     actor_id,
     splitByString('/xblock/', object_id)[-1] as block_id,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     org,
     verb_id,
     JSONExtractString(event, 'object', 'definition', 'type') as object_type,

models/problems/problem_events.sql

@@ -15,7 +15,7 @@ select
     cast(emission_time as DateTime) as emission_time,
     actor_id,
     object_id,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     org,
     verb_id,
     JSON_VALUE(event, '$.result.response') as responses,
@@ -25,7 +25,9 @@ select
         cast(JSON_VALUE(event, '$.result.success') as Bool),
         false
     ) as success,
-    JSON_VALUE(event, '$.object.definition.interactionType') as interaction_type,
+    toLowCardinality(
+        JSON_VALUE(event, '$.object.definition.interactionType')
+    ) as interaction_type,
     if(
         verb_id = 'https://w3id.org/xapi/acrossx/verbs/evaluated',
         cast(

models/video/video_playback_events.sql

@@ -15,7 +15,7 @@ select
     CAST(emission_time, 'DateTime') as emission_time,
     actor_id,
     object_id,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     org,
     verb_id,
     ceil(

models/video/video_transcript_events.sql

@@ -14,7 +14,7 @@ select
     event_id,
     CAST(emission_time, 'DateTime') as emission_time,
     org,
-    splitByString('/', course_id)[-1] as course_key,
+    course_key,
     splitByString('/xblock/', object_id)[2] as video_id,
     actor_id,
     JSONExtractBool(
@@ -25,7 +25,7 @@ select
     ) as cc_enabled
 from {{ ref("xapi_events_all_parsed") }}
 where
-    verb_id in ('http://adlnet.gov/expapi/verbs/interacted')
+    verb_id = 'http://adlnet.gov/expapi/verbs/interacted'
     and JSONHas(
         event,
         'result',