perf(gtfs): cache service_days matview existence per schema

getDepartures/getArrivals/getDeparturesByDate each ran a pg_matviews
EXISTS check on every call. Cache it per schema, mirroring the existing
hasOriginalStopIdColumn pattern, invalidated by invalidateSchemaCaches
on feed (re)import.

Author: Medformatik

apps/api/src/services/gtfs/queries.test.ts

@@ -0,0 +1,57 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+const unsafe = vi.fn();
+vi.mock("./db", () => ({ sql: { unsafe: (...args: unknown[]) => unsafe(...args) } }));
+
+function isMatviewCheck(query: string): boolean {
+  return query.includes("pg_matviews");
+}
+
+beforeEach(() => {
+  unsafe.mockReset();
+  // Matview check → exists; any other query → empty result set.
+  unsafe.mockImplementation(async (query: string) =>
+    isMatviewCheck(query) ? [{ exists: true }] : [],
+  );
+});
+
+afterEach(() => {
+  vi.resetModules();
+});
+
+describe("service_days matview existence cache", () => {
+  it("checks pg_matviews once per schema across repeated departure queries", async () => {
+    vi.resetModules();
+    const q = await import("./queries");
+    await q.getDepartures("gtfs_ch", "stop-1", 60);
+    await q.getDepartures("gtfs_ch", "stop-1", 60);
+    await q.getArrivals("gtfs_ch", "stop-1", 60);
+
+    const matviewCalls = unsafe.mock.calls.filter(([query]) => isMatviewCheck(query as string));
+    expect(matviewCalls).toHaveLength(1);
+  });
+
+  it("re-checks pg_matviews after invalidateSchemaCaches", async () => {
+    vi.resetModules();
+    const q = await import("./queries");
+    await q.getDepartures("gtfs_ch", "stop-1", 60);
+    q.invalidateSchemaCaches("gtfs_ch");
+    await q.getDepartures("gtfs_ch", "stop-1", 60);
+
+    const matviewCalls = unsafe.mock.calls.filter(([query]) => isMatviewCheck(query as string));
+    expect(matviewCalls).toHaveLength(2);
+  });
+
+  it("caches the negative result (matview missing → empty, no re-check)", async () => {
+    unsafe.mockImplementation(async (query: string) =>
+      isMatviewCheck(query) ? [{ exists: false }] : [],
+    );
+    vi.resetModules();
+    const q = await import("./queries");
+    expect(await q.getDepartures("gtfs_none", "stop-1", 60)).toEqual([]);
+    expect(await q.getDepartures("gtfs_none", "stop-1", 60)).toEqual([]);
+
+    const matviewCalls = unsafe.mock.calls.filter(([query]) => isMatviewCheck(query as string));
+    expect(matviewCalls).toHaveLength(1);
+  });
+});

apps/api/src/services/gtfs/queries.ts

@@ -140,16 +140,7 @@ export async function getDepartures(
   minutes: number,
 ): Promise<GtfsDepartureRow[]> {
   assertValidGtfsSchema(schema);
-  // Check if service_days view exists
-  const viewCheck = await sql.unsafe(
-    `
-    SELECT EXISTS (
-      SELECT 1 FROM pg_matviews WHERE schemaname = $1 AND matviewname = 'service_days'
-    ) as exists
-  `,
-    [schema],
-  );
-  if (!viewCheck[0]?.exists) return [];
+  if (!(await hasServiceDaysView(schema))) return [];
 
   const rows = await sql.unsafe(
     `
@@ -189,15 +180,7 @@ export async function getArrivals(
   minutes: number,
 ): Promise<GtfsDepartureRow[]> {
   assertValidGtfsSchema(schema);
-  const viewCheck = await sql.unsafe(
-    `
-    SELECT EXISTS (
-      SELECT 1 FROM pg_matviews WHERE schemaname = $1 AND matviewname = 'service_days'
-    ) as exists
-  `,
-    [schema],
-  );
-  if (!viewCheck[0]?.exists) return [];
+  if (!(await hasServiceDaysView(schema))) return [];
 
   const rows = await sql.unsafe(
     `
@@ -258,15 +241,7 @@ export async function getDeparturesByDate(
   date: string,
 ): Promise<GtfsDepartureRow[]> {
   assertValidGtfsSchema(schema);
-  const viewCheck = await sql.unsafe(
-    `
-    SELECT EXISTS (
-      SELECT 1 FROM pg_matviews WHERE schemaname = $1 AND matviewname = 'service_days'
-    ) as exists
-    `,
-    [schema],
-  );
-  if (!viewCheck[0]?.exists) return [];
+  if (!(await hasServiceDaysView(schema))) return [];
 
   const rows = await sql.unsafe(
     `
@@ -324,10 +299,30 @@ export async function getSchemaStats(
 }
 
 const schemaStopOriginalIdSupport = new Map<string, boolean>();
+const schemaServiceDaysSupport = new Map<string, boolean>();
 
 /** Invalidate per-schema metadata caches. Call before/after a schema is dropped or re-imported. */
 export function invalidateSchemaCaches(schema: string): void {
   schemaStopOriginalIdSupport.delete(schema);
+  schemaServiceDaysSupport.delete(schema);
+}
+
+async function hasServiceDaysView(schema: string): Promise<boolean> {
+  assertValidGtfsSchema(schema);
+  const cached = schemaServiceDaysSupport.get(schema);
+  if (cached !== undefined) return cached;
+
+  const rows = await sql.unsafe(
+    `
+    SELECT EXISTS (
+      SELECT 1 FROM pg_matviews WHERE schemaname = $1 AND matviewname = 'service_days'
+    ) as exists
+  `,
+    [schema],
+  );
+  const exists = rows[0]?.exists === true;
+  schemaServiceDaysSupport.set(schema, exists);
+  return exists;
 }
 
 async function hasOriginalStopIdColumn(schema: string): Promise<boolean> {