From 46df12c025dc3e9c9fd813e2e578be62b2fe07f7 Mon Sep 17 00:00:00 2001
From: Albrecht Degering <albrecht@degering.name>
Date: Thu, 30 Jul 2026 01:15:38 +0200
Subject: [PATCH] perf(campaign): batch tenant summaries

---
 src/govoplan_campaign/backend/manifest.py | 21 +++++++
 tests/test_tenant_summary_batch.py        | 77 +++++++++++++++++++++++
 2 files changed, 98 insertions(+)
 create mode 100644 tests/test_tenant_summary_batch.py

diff --git a/src/govoplan_campaign/backend/manifest.py b/src/govoplan_campaign/backend/manifest.py
index 5061d2b..5c3bcba 100644
--- a/src/govoplan_campaign/backend/manifest.py
+++ b/src/govoplan_campaign/backend/manifest.py
@@ -161,6 +161,26 @@ def _tenant_summary(session, tenant_id: str) -> dict[str, int]:
     return {"campaigns": session.query(Campaign).filter(Campaign.tenant_id == tenant_id).count()}
 
 
+def _tenant_summary_batch(session, tenant_ids) -> dict[str, dict[str, int]]:
+    from sqlalchemy import func
+
+    from govoplan_campaign.backend.db.models import Campaign
+
+    ids = tuple(dict.fromkeys(str(tenant_id) for tenant_id in tenant_ids if tenant_id))
+    if not ids:
+        return {}
+    rows = (
+        session.query(Campaign.tenant_id, func.count(Campaign.id))
+        .filter(Campaign.tenant_id.in_(ids))
+        .group_by(Campaign.tenant_id)
+        .all()
+    )
+    return {
+        tenant_id: {"campaigns": int(count)}
+        for tenant_id, count in rows
+    }
+
+
 def _campaigns_router(context: ModuleContext):
     from govoplan_campaign.backend.runtime import configure_runtime
 
@@ -236,6 +256,7 @@ manifest = ModuleManifest(
     route_factory=_campaigns_router,
     role_templates=ROLE_TEMPLATES,
     tenant_summary_providers=(_tenant_summary,),
+    tenant_summary_batch_providers=(_tenant_summary_batch,),
     nav_items=(
         NavItem(path="/campaigns", label="Campaigns", icon="campaign", required_any=CAMPAIGN_MODULE_REQUIRED_ANY, order=20),
     ),
diff --git a/tests/test_tenant_summary_batch.py b/tests/test_tenant_summary_batch.py
new file mode 100644
index 0000000..405ba32
--- /dev/null
+++ b/tests/test_tenant_summary_batch.py
@@ -0,0 +1,77 @@
+from __future__ import annotations
+
+import unittest
+
+from sqlalchemy import create_engine, event
+from sqlalchemy.orm import Session
+
+from govoplan_access.backend.db.models import Account, Group, User
+from govoplan_campaign.backend.db.models import Campaign
+from govoplan_campaign.backend.manifest import _tenant_summary_batch
+from govoplan_core.core.change_sequence import ChangeSequenceEntry
+from govoplan_core.db.base import Base
+
+
+class CampaignTenantSummaryBatchTests(unittest.TestCase):
+    def test_batch_summary_groups_all_tenants_in_one_query(self) -> None:
+        engine = create_engine("sqlite+pysqlite:///:memory:")
+        Base.metadata.create_all(
+            engine,
+            tables=[
+                Account.__table__,
+                User.__table__,
+                Group.__table__,
+                Campaign.__table__,
+                ChangeSequenceEntry.__table__,
+            ],
+        )
+        try:
+            with Session(engine) as session:
+                session.add_all(
+                    [
+                        Campaign(
+                            id="campaign-1",
+                            tenant_id="tenant-1",
+                            external_id="one",
+                            name="One",
+                        ),
+                        Campaign(
+                            id="campaign-2",
+                            tenant_id="tenant-1",
+                            external_id="two",
+                            name="Two",
+                        ),
+                        Campaign(
+                            id="campaign-3",
+                            tenant_id="tenant-2",
+                            external_id="three",
+                            name="Three",
+                        ),
+                    ]
+                )
+                session.commit()
+                query_count = 0
+
+                def count_query(*_args: object) -> None:
+                    nonlocal query_count
+                    query_count += 1
+
+                event.listen(engine, "before_cursor_execute", count_query)
+                try:
+                    counts = _tenant_summary_batch(
+                        session,
+                        ["tenant-1", "tenant-2", "tenant-empty"],
+                    )
+                finally:
+                    event.remove(engine, "before_cursor_execute", count_query)
+
+            self.assertEqual(1, query_count)
+            self.assertEqual({"campaigns": 2}, counts["tenant-1"])
+            self.assertEqual({"campaigns": 1}, counts["tenant-2"])
+            self.assertNotIn("tenant-empty", counts)
+        finally:
+            engine.dispose()
+
+
+if __name__ == "__main__":
+    unittest.main()