From 68e94f14186d74ff608444c1936430df016f6a96 Mon Sep 17 00:00:00 2001
From: Michael Bunsen <notbot@gmail.com>
Date: Tue, 3 Dec 2024 21:51:57 -0800
Subject: [PATCH] fix: reduce the number of queries in each page of occurrences

---
 ami/main/api/serializers.py | 6 +++---
 ami/main/api/views.py       | 2 ++
 ami/main/models.py          | 7 +++++++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/ami/main/api/serializers.py b/ami/main/api/serializers.py
index c36ccca3a..eb7164489 100644
--- a/ami/main/api/serializers.py
+++ b/ami/main/api/serializers.py
@@ -1061,7 +1061,9 @@ class Meta:
         ]
 
     def get_determination_details(self, obj: Occurrence):
-        # @TODO add an equivalent method to the Occurrence model
+        # @TODO convert this to query methods to avoid N+1 queries.
+        # Currently at 100+ queries per page of 10 occurrences.
+        # Add a reusable method to the OccurrenceQuerySet class and call it from the ViewSet.
 
         context = self.context
 
@@ -1091,7 +1093,6 @@ def get_determination_details(self, obj: Occurrence):
 class OccurrenceSerializer(OccurrenceListSerializer):
     determination = CaptureTaxonSerializer(read_only=True)
     detections = DetectionNestedSerializer(many=True, read_only=True)
-    identifications = OccurrenceIdentificationSerializer(many=True, read_only=True)
     predictions = OccurrenceClassificationSerializer(many=True, read_only=True)
     deployment = DeploymentNestedSerializer(read_only=True)
     event = EventNestedSerializer(read_only=True)
@@ -1102,7 +1103,6 @@ class Meta:
         fields = OccurrenceListSerializer.Meta.fields + [
             "determination_id",
             "detections",
-            "identifications",
             "predictions",
         ]
         read_only_fields = [
diff --git a/ami/main/api/views.py b/ami/main/api/views.py
index bc6ed96d1..5b1f2cf10 100644
--- a/ami/main/api/views.py
+++ b/ami/main/api/views.py
@@ -925,6 +925,8 @@ def get_queryset(self) -> QuerySet:
             "event",
         )
         qs = qs.with_detections_count().with_timestamps()  # type: ignore
+        qs = qs.with_identifications()  # type: ignore
+
         if self.action == "list":
             qs = (
                 qs.all()
diff --git a/ami/main/models.py b/ami/main/models.py
index 84a7e3bf1..fce015aab 100644
--- a/ami/main/models.py
+++ b/ami/main/models.py
@@ -1945,6 +1945,13 @@ def with_timestamps(self) -> models.QuerySet:
             ),
         )
 
+    def with_identifications(self) -> models.QuerySet:
+        return self.prefetch_related(
+            "identifications",
+            "identifications__taxon",
+            "identifications__user",
+        )
+
 
 class OccurrenceManager(models.Manager):
     def get_queryset(self) -> OccurrenceQuerySet: