refactor: optimize applications overview (#6548)

There was no need to join the entire metrics table, as it is a huge
table. We only needed all combinations of app_name, environment, and
feature_name. The new query retrieves all this data, which will then be
joined into the main query.

src/lib/db/client-applications-store.ts

@@ -292,6 +292,13 @@ export default class ClientApplicationsStore
         appName: string,
     ): Promise<IApplicationOverview> {
         const query = this.db
+            .with('metrics', (qb) => {
+                qb.distinct(
+                    'cme.app_name',
+                    'cme.environment',
+                    'cme.feature_name',
+                ).from('client_metrics_env as cme');
+            })
             .select([
                 'f.project',
                 'cme.environment',
@@ -302,7 +309,7 @@ export default class ClientApplicationsStore
                 'a.strategies',
             ])
             .from({ a: 'client_applications' })
-            .leftJoin('client_metrics_env as cme', 'cme.app_name', 'a.app_name')
+            .leftJoin('metrics as cme', 'cme.app_name', 'a.app_name')
             .leftJoin('features as f', 'cme.feature_name', 'f.name')
             .leftJoin('client_instances as ci', function () {
                 this.on('ci.app_name', '=', 'cme.app_name').andOn(