From 85e947a337deb8188eeb547ce08c7d8f0149dcde Mon Sep 17 00:00:00 2001
From: Joaquim d'Souza <joaquimds@gmail.com>
Date: Wed, 4 Feb 2026 11:54:22 +0100
Subject: [PATCH 1/2] feat: add read replica for expensive geocode query

---
 src/server/commands/ensureOrganisationMap.ts |  9 ++++--
 src/server/repositories/Area.ts              |  5 +--
 src/server/services/database/index.ts        | 32 +++++++++++++++-----
 3 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/src/server/commands/ensureOrganisationMap.ts b/src/server/commands/ensureOrganisationMap.ts
index b1990c66..f188e65c 100644
--- a/src/server/commands/ensureOrganisationMap.ts
+++ b/src/server/commands/ensureOrganisationMap.ts
@@ -20,7 +20,11 @@ import {
 } from "@/server/repositories/MapView";
 import { upsertOrganisation } from "@/server/repositories/Organisation";
 import { AreaSetCode, AreaSetGroupCode } from "../models/AreaSet";
-import { ColorScheme, MapStyleName } from "../models/MapView";
+import {
+  ColorScheme,
+  DEFAULT_CALCULATION_TYPE,
+  MapStyleName,
+} from "../models/MapView";
 import { countDataRecordsForDataSource } from "../repositories/DataRecord";
 import type { MapView } from "../models/MapView";
 import type { DataSource } from "@/server/models/DataSource";
@@ -87,11 +91,12 @@ const ensureOrganisationMap = async (orgId: string): Promise<Map> => {
       areaDataColumn: "Lab",
       areaDataSourceId: electionResultsDataSource.id,
       areaSetGroupCode: AreaSetGroupCode.WMC24,
-      calculationType: null,
+      calculationType: DEFAULT_CALCULATION_TYPE,
       colorScheme: ColorScheme.GreenYellowRed,
       mapStyleName: MapStyleName.Light,
       reverseColorScheme: false,
       showBoundaryOutline: true,
+      showChoropleth: true,
       showLabels: true,
       showLocations: true,
       showMembers: true,
diff --git a/src/server/repositories/Area.ts b/src/server/repositories/Area.ts
index c78dc35b..7f6bada0 100644
--- a/src/server/repositories/Area.ts
+++ b/src/server/repositories/Area.ts
@@ -1,5 +1,5 @@
 import { sql } from "kysely";
-import { db } from "@/server/services/database";
+import { db, dbRead } from "@/server/services/database";
 import type { Area } from "@/server/models/Area";
 import type { AreaSetCode } from "@/server/models/AreaSet";
 import type { Database } from "@/server/services/database";
@@ -82,7 +82,8 @@ export async function findAreasByPoint({
   excludeAreaSetCode?: AreaSetCode | null | undefined;
   includeAreaSetCode?: AreaSetCode | null | undefined;
 }): Promise<AreaWithAreaSetCode[]> {
-  let query = db
+  // Use the read replica for this expensive read query
+  let query = dbRead
     .selectFrom("area")
     .innerJoin("areaSet", "area.areaSetId", "areaSet.id");
   if (excludeAreaSetCode) {
diff --git a/src/server/services/database/index.ts b/src/server/services/database/index.ts
index 6e8b3732..38175047 100644
--- a/src/server/services/database/index.ts
+++ b/src/server/services/database/index.ts
@@ -25,11 +25,23 @@ export const pool = new Pool({
   max: Number(process.env.DATABASE_POOL_SIZE) || undefined,
 });
 
+// Set up read replica pool with graceful fallback
+const readReplicaPool = new Pool({
+  connectionString:
+    process.env.DATABASE_READ_REPLICA_URL || process.env.DATABASE_URL,
+  max: Number(process.env.DATABASE_POOL_SIZE) || undefined,
+});
+
 const dialect = new PostgresDialect({
   cursor: Cursor,
   pool,
 });
 
+const readReplicaDialect = new PostgresDialect({
+  cursor: Cursor,
+  pool: readReplicaPool,
+});
+
 export interface Database {
   airtableWebhook: AirtableWebhookTable;
   area: AreaTable;
@@ -49,14 +61,20 @@ export interface Database {
   "pgboss.job": JobTable;
 }
 
+const sharedPlugins = [
+  new CamelCasePlugin({ maintainNestedObjectKeys: true }),
+  new PointPlugin(),
+  new JSONPlugin(),
+];
+
 export const db = new Kysely<Database>({
   dialect,
-  plugins: [
-    // Database `field_name` to TypeScript `fieldName`.
-    // `maintainNestedObjectKeys` prevents `data_record.json` being mangled
-    new CamelCasePlugin({ maintainNestedObjectKeys: true }),
-    new PointPlugin(),
-    new JSONPlugin(),
-  ],
+  plugins: sharedPlugins,
+  log: ["error"],
+});
+
+export const dbRead = new Kysely<Database>({
+  dialect: readReplicaDialect,
+  plugins: sharedPlugins,
   log: ["error"],
 });

From a6c9bb86884306a972b89093021e0ae30c8a6cc9 Mon Sep 17 00:00:00 2001
From: Joaquim d'Souza <joaquimds@gmail.com>
Date: Wed, 4 Feb 2026 17:12:13 +0100
Subject: [PATCH 2/2] feat: add area (area_set_id, geography) combined index
 for improved geocoding queries

---
 .../1770221306067_area_set_id_geography_index.ts   | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 migrations/1770221306067_area_set_id_geography_index.ts

diff --git a/migrations/1770221306067_area_set_id_geography_index.ts b/migrations/1770221306067_area_set_id_geography_index.ts
new file mode 100644
index 00000000..e3d8133f
--- /dev/null
+++ b/migrations/1770221306067_area_set_id_geography_index.ts
@@ -0,0 +1,14 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+import { type Kysely, sql } from "kysely";
+
+export async function up(db: Kysely<any>): Promise<void> {
+  await sql`CREATE EXTENSION IF NOT EXISTS btree_gist`.execute(db);
+  await sql`CREATE INDEX area_area_set_id_geography_gist ON area USING GIST (area_set_id, geography)`.execute(
+    db,
+  );
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await sql`DROP INDEX IF EXISTS area_area_set_id_geography_gist`.execute(db);
+  await sql`DROP EXTENSION IF EXISTS btree_gist`.execute(db);
+}