Reduce number of queries in the courses api

DFE-Digital · Oct 25, 2024 · 0d446ef · 0d446ef
1 parent 292ac6f
commit 0d446ef
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Showing 3 changed files with 9 additions and 2 deletions.
diff --git a/app/models/course.rb b/app/models/course.rb
@@ -585,6 +585,8 @@ def gcse_grade_required
   end
 
   def last_published_at
+    return enrichments.max_by(&:last_published_timestamp_utc).last_published_timestamp_utc if enrichments.loaded?
+
     enrichments.maximum(:last_published_timestamp_utc)
   end
 

diff --git a/app/models/required_qualifications_summary.rb b/app/models/required_qualifications_summary.rb
@@ -8,7 +8,12 @@ def initialize(course)
   end
 
   def extract
-    legacy_qualifications_attribute = course.latest_published_enrichment&.required_qualifications
+    # This performance improvement saves ~100 database queries in the courses api endpoint
+    legacy_qualifications_attribute = if course.enrichments.loaded?
+                                        course.enrichments.max_by(&:created_at)&.required_qualifications
+                                      else
+                                        course.latest_published_enrichment&.required_qualifications
+                                      end
     return legacy_qualifications_attribute if legacy_qualifications_attribute.present?
 
     generate_summary_text

diff --git a/app/serializers/api/public/v1/serializable_course.rb b/app/serializers/api/public/v1/serializable_course.rb
@@ -11,7 +11,7 @@ class SerializableCourse < JSONAPI::Serializable::Resource
         class << self
           def enrichment_attribute(name, enrichment_name = name)
             attribute name do
-              @object.latest_published_enrichment&.public_send(enrichment_name)
+              @object.enrichments.max_by(&:created_at)&.public_send(enrichment_name)
             end
           end
         end