Validate also that if query halts readiness fails

src/lib/routes/ready-check.ts

@@ -81,9 +81,22 @@ export class ReadyCheckController extends Controller {
         }
 
         try {
-            connection.query({
+            await connection.query('BEGIN');
-                text: 'SELECT 1',
+            await connection.query({
+                text: `SET LOCAL statement_timeout = ${timeoutMs}`,
             });
+            await connection.query('SELECT 1');
+            await connection.query('COMMIT');
+        } catch (error) {
+            try {
+                await connection.query('ROLLBACK');
+            } catch (rollbackError) {
+                this.logger.debug(
+                    'Failed to rollback readiness timeout transaction',
+                    rollbackError,
+                );
+            }
+            throw error;
         } finally {
             if (connection) {
                 await client.releaseConnection(connection);

src/lib/types/option.ts

@@ -302,6 +302,5 @@ export interface IUnleashConfig {
     userInactivityThresholdInDays: number;
     buildDate?: string;
     unleashFrontendToken?: string;
-    /** If true, the readiness endpoint will attempt a simple Postgres query to verify DB availability */
     checkDbOnReady?: boolean;
 }

src/test/e2e/ready.e2e.test.ts

@@ -29,6 +29,46 @@ describe('DB is up', () => {
         );
         await request.get('/ready').expect(200).expect('{"health":"GOOD"}');
     });
+
+    test('fails fast when readiness query hangs', async () => {
+        const { request } = await setupAppWithCustomConfig(
+            db.stores,
+            { checkDbOnReady: true },
+            db.rawDatabase,
+        );
+
+        const pool = db.rawDatabase.client.pool;
+        const originalAcquire = pool.acquire.bind(pool);
+
+        pool.acquire = () => {
+            const pending = originalAcquire();
+            pending.promise = pending.promise.then((conn: any) => {
+                const originalQuery = conn.query;
+                conn.query = (queryConfig: any, ...args: any[]) => {
+                    const isSelectOne =
+                        queryConfig?.toUpperCase() === 'SELECT 1';
+
+                    if (isSelectOne) {
+                        return originalQuery.call(
+                            conn,
+                            'SELECT pg_sleep(1)',
+                            ...args,
+                        );
+                    }
+
+                    return originalQuery.call(conn, queryConfig, ...args);
+                };
+                return conn;
+            });
+            return pending;
+        };
+
+        try {
+            await request.get('/ready').expect(503);
+        } finally {
+            pool.acquire = originalAcquire;
+        }
+    });
 });
 
 describe('DB is down', () => {