enhance sub-issue query performance with optimized annotations and subqueries (#8889)

Author: PhuongPN6689

apps/api/plane/app/views/issue/sub_issue.py

@@ -7,7 +7,7 @@
 
 # Django imports
 from django.utils import timezone
-from django.db.models import OuterRef, Func, F, Q, Value, UUIDField, Subquery
+from django.db.models import OuterRef, Func, F, Q, Value, UUIDField, Subquery, Count, IntegerField
 from django.utils.decorators import method_decorator
 from django.views.decorators.gzip import gzip_page
 from django.contrib.postgres.aggregates import ArrayAgg
@@ -22,7 +22,7 @@
 from .. import BaseAPIView
 from plane.app.serializers import IssueSerializer
 from plane.app.permissions import ProjectEntityPermission
-from plane.db.models import Issue, IssueLink, FileAsset, CycleIssue
+from plane.db.models import Issue, IssueLink, FileAsset, CycleIssue, IssueLabel, IssueAssignee, ModuleIssue
 from plane.bgtasks.issue_activities_task import issue_activity
 from plane.utils.timezone_converter import user_timezone_converter
 from collections import defaultdict
@@ -37,70 +37,97 @@ class SubIssuesEndpoint(BaseAPIView):
     def get(self, request, slug, project_id, issue_id):
         sub_issues = (
             Issue.issue_objects.filter(parent_id=issue_id, workspace__slug=slug)
-            .select_related("workspace", "project", "state", "parent")
-            .prefetch_related("assignees", "labels", "issue_module__module")
             .annotate(
                 cycle_id=Subquery(
                     CycleIssue.objects.filter(issue=OuterRef("id"), deleted_at__isnull=True).values("cycle_id")[:1]
                 )
             )
             .annotate(
-                link_count=IssueLink.objects.filter(issue=OuterRef("id"))
-                .order_by()
-                .annotate(count=Func(F("id"), function="Count"))
-                .values("count")
+                link_count=Coalesce(
+                    Subquery(
+                        IssueLink.objects.filter(issue=OuterRef("id"))
+                        .order_by()
+                        .values("issue")
+                        .annotate(count=Count("id"))
+                        .values("count"),
+                        output_field=IntegerField(),
+                    ),
+                    0,
+                )
             )
             .annotate(
-                attachment_count=FileAsset.objects.filter(
-                    issue_id=OuterRef("id"),
-                    entity_type=FileAsset.EntityTypeContext.ISSUE_ATTACHMENT,
+                attachment_count=Coalesce(
+                    Subquery(
+                        FileAsset.objects.filter(
+                            issue_id=OuterRef("id"),
+                            entity_type=FileAsset.EntityTypeContext.ISSUE_ATTACHMENT,
+                        )
+                        .order_by()
+                        .values("issue_id")
+                        .annotate(count=Count("id"))
+                        .values("count"),
+                        output_field=IntegerField(),
+                    ),
+                    0,
                 )
-                .order_by()
-                .annotate(count=Func(F("id"), function="Count"))
-                .values("count")
             )
             .annotate(
-                sub_issues_count=Issue.issue_objects.filter(parent=OuterRef("id"))
-                .order_by()
-                .annotate(count=Func(F("id"), function="Count"))
-                .values("count")
+                sub_issues_count=Coalesce(
+                    Subquery(
+                        Issue.issue_objects.filter(parent=OuterRef("id"))
+                        .order_by()
+                        .values("parent")
+                        .annotate(count=Count("id"))
+                        .values("count"),
+                        output_field=IntegerField(),
+                    ),
+                    0,
+                )
             )
             .annotate(
                 label_ids=Coalesce(
-                    ArrayAgg(
-                        "labels__id",
-                        distinct=True,
-                        filter=Q(~Q(labels__id__isnull=True) & Q(label_issue__deleted_at__isnull=True)),
+                    Subquery(
+                        IssueLabel.objects.filter(issue_id=OuterRef("id"), deleted_at__isnull=True)
+                        .order_by()
+                        .values("issue_id")
+                        .annotate(arr=ArrayAgg("label_id", distinct=True))
+                        .values("arr"),
+                        output_field=ArrayField(UUIDField()),
                     ),
                     Value([], output_field=ArrayField(UUIDField())),
                 ),
                 assignee_ids=Coalesce(
-                    ArrayAgg(
-                        "assignees__id",
-                        distinct=True,
-                        filter=Q(
-                            ~Q(assignees__id__isnull=True)
-                            & Q(assignees__member_project__is_active=True)
-                            & Q(issue_assignee__deleted_at__isnull=True)
-                        ),
+                    Subquery(
+                        IssueAssignee.objects.filter(
+                            issue_id=OuterRef("id"),
+                            assignee__member_project__is_active=True,
+                            deleted_at__isnull=True,
+                        )
+                        .order_by()
+                        .values("issue_id")
+                        .annotate(arr=ArrayAgg("assignee_id", distinct=True))
+                        .values("arr"),
+                        output_field=ArrayField(UUIDField()),
                     ),
                     Value([], output_field=ArrayField(UUIDField())),
                 ),
                 module_ids=Coalesce(
-                    ArrayAgg(
-                        "issue_module__module_id",
-                        distinct=True,
-                        filter=Q(
-                            ~Q(issue_module__module_id__isnull=True)
-                            & Q(issue_module__module__archived_at__isnull=True)
-                            & Q(issue_module__deleted_at__isnull=True)
-                        ),
+                    Subquery(
+                        ModuleIssue.objects.filter(
+                            issue_id=OuterRef("id"),
+                            module__archived_at__isnull=True,
+                            deleted_at__isnull=True,
+                        )
+                        .order_by()
+                        .values("issue_id")
+                        .annotate(arr=ArrayAgg("module_id", distinct=True))
+                        .values("arr"),
+                        output_field=ArrayField(UUIDField()),
                     ),
                     Value([], output_field=ArrayField(UUIDField())),
                 ),
             )
             .annotate(state_group=F("state__group"))
-            .order_by("-created_at")
         )
 
         # Ordering
@@ -110,38 +137,42 @@ def get(self, request, slug, project_id, issue_id):
         if order_by_param:
             sub_issues, order_by_param = order_issue_queryset(sub_issues, order_by_param)
 
+        sub_issues = list(
+            sub_issues.values(
+                "id",
+                "name",
+                "state_id",
+                "sort_order",
+                "completed_at",
+                "estimate_point",
+                "priority",
+                "start_date",
+                "target_date",
+                "sequence_id",
+                "project_id",
+                "parent_id",
+                "cycle_id",
+                "module_ids",
+                "label_ids",
+                "assignee_ids",
+                "sub_issues_count",
+                "created_at",
+                "updated_at",
+                "created_by",
+                "updated_by",
+                "attachment_count",
+                "link_count",
+                "is_draft",
+                "archived_at",
+                "state_group",
+            )
+        )
+
         # create's a dict with state group name with their respective issue id's
         result = defaultdict(list)
         for sub_issue in sub_issues:
-            result[sub_issue.state_group].append(str(sub_issue.id))
+            result[sub_issue["state_group"]].append(str(sub_issue["id"]))
 
-        sub_issues = sub_issues.values(
-            "id",
-            "name",
-            "state_id",
-            "sort_order",
-            "completed_at",
-            "estimate_point",
-            "priority",
-            "start_date",
-            "target_date",
-            "sequence_id",
-            "project_id",
-            "parent_id",
-            "cycle_id",
-            "module_ids",
-            "label_ids",
-            "assignee_ids",
-            "sub_issues_count",
-            "created_at",
-            "updated_at",
-            "created_by",
-            "updated_by",
-            "attachment_count",
-            "link_count",
-            "is_draft",
-            "archived_at",
-        )
         datetime_fields = ["created_at", "updated_at"]
         sub_issues = user_timezone_converter(sub_issues, datetime_fields, request.user.user_timezone)
         # Grouping