Performance Optimization

# Performance Optimization

How the platform achieves fast page loads, efficient data fetching, and observable performance.

## Data Fetching Architecture

Three layers work together to minimize database roundtrips:

### Layer 1: Cross-Request Cache (Next.js Data Cache)

Stable, tenant-scoped data is cached across requests via `unstable_cache`. The cache persists until explicitly invalidated or the TTL expires (1 week safety net).

**What's cached:**
- Entity types (`getCachedEntityTypes`) — `entity-types-{tenantId}` tag
- Entity type by slug (`getCachedEntityTypeBySlug`) — same tag
- Tenant nav config (`getCachedTenantNavOverride`) — `nav-config-{tenantId}` tag

**Invalidation:** Every mutation path calls `invalidateEntityTypesCache(tenantId)` or `invalidateNavConfigCache(tenantId)`. These are centralized helpers — all code paths (server actions, admin tools, API routes) use them.

**Pattern:**
```typescript
// features/entities/server/cached-queries.ts
export async function getCachedEntityTypes(tenantId: string) {
  const cached = unstable_cache(
    async () => {
      const supabase = createAdminClient();
      return listAccessibleEntityTypes(supabase, tenantId);
    },
    [`entity-types-${tenantId}`],
    { tags: [`entity-types`, `entity-types-${tenantId}`], revalidate: 604800 }
  );
  return cached();
}
```

### Layer 2: Per-Request Dedup (React.cache)

Functions called from multiple server components in the same render are wrapped in `React.cache()` to execute only once per request.

**Cached functions:**
- `getEntityTypes()` — layout + pages
- `getEntityById()` — entity detail
- `getTenantContext()` — nearly every server action
- `getUserPermissions()` — permission checks
- `getEntityCounts()` — dashboard + sidebar
- `getResolvedNavConfig()` — layout
- `getDisabledToolSlugs()` — tool registry

### Layer 3: Client-Side Cache (React Query)

Client components use React Query for caching, deduplication, and stale-while-revalidate.

**Stale times by data type:**
- Chat messages, workflows: 15-30 seconds
- Entities, comments, feed: 60 seconds
- Entity types, counts: 5 minutes

**initialData bridging:** Hooks accept `initialData` from SSR props to prevent double-fetch:
```typescript
export function useEntityTypes(options?: { initialData?: EntityTypeRecord[] }) {
  return useQuery({
    queryKey: entityTypesQueryKey(),
    queryFn: fetchEntityTypes,
    staleTime: 5 * 60 * 1000,
    initialData: options?.initialData,
  });
}
```

## Code Splitting

Zero-cost lazy loading for heavy libraries.

### Dynamic Shell Components

CommandPalette and ChatDockShell are mounted on every page but loaded via `next/dynamic` with `ssr: false`:

```typescript
// components/app-shell/lazy-shell.tsx
export const LazyCommandPalette = dynamic(
  () => import("@/components/app-shell/command-palette").then(m => ({ default: m.CommandPalette })),
  { ssr: false }
);
```

### Lazy Block Registry

Heavy block types (chart, radar, bubble-chart, entity-graph) are lazy-loaded via `createLazyBlock()`:

```typescript
const LazyChartBlock = createLazyBlock(() =>
  import("./chart-block").then(m => ({ default: m.ChartBlock }))
);
registerBlock("chart", { component: LazyChartBlock, defaultSize: "half" });
```

Core blocks (stat-cards, table, field-card, etc.) are always bundled.

### Graph Visualization

`@xyflow/react` (~120KB) is lazy-loaded on the `/graph` page via `next/dynamic`.

## Performance Monitoring

### Sentry Supabase Integration

`supabaseIntegration()` is enabled in both client and server Sentry configs:
- Automatic `db.select/insert/update/delete` spans for every Supabase query
- RLS error capture (previously silent failures)
- Feeds **Sentry Query Insights** dashboard

### Stuck Skeleton Detection

`NavigationTimingProvider` mounted in the app shell measures page navigation timing. Pages taking >3 seconds trigger a Sentry warning with pathname and duration.

### Server Action Timing

`measure()` from `lib/performance/measure.ts` wraps slow server actions:
```typescript
const result = await measure("searchEntities", () => fetchEntities(params));
```

### Supabase Dashboard

`pg_stat_statements` is enabled — use Dashboard > Query Performance to find slow server-side queries and get Index Advisor recommendations.

## Adding a New Cached Query

1. Create the cached function in the appropriate `cached-queries.ts` using `unstable_cache`
2. Use `createAdminClient()` (no cookies dependency)
3. Pass `tenantId` as parameter (becomes cache key)
4. Add tags for invalidation
5. Create an `invalidateXCache(tenantId)` helper
6. Call the invalidation helper from ALL mutation paths
7. Wrap the caller in `React.cache()` for per-request dedup

## Migration to `use cache`

When `cacheComponents: true` is stable (currently breaks prerendering on some pages), migrate `unstable_cache` to `'use cache'` + `cacheLife()` + `cacheTag()`. The pattern is identical but uses compiler directives instead of function wrappers. See the `next-cache-components` skill for details.

## Database Performance

For Postgres-level optimization (RLS policies, indexes, functions, pgTAP testing), see the [Database Optimization runbook](/docs/runbooks/database-optimization).

Key database optimizations applied:
- **RLS auth.uid() wrapping** — All policies use `(SELECT auth.uid())` for per-query caching
- **authorize() tenant scoping** — Permission checks scoped to active tenant only
- **Index deduplication** — Reduced entities indexes from 27→17 (37% fewer writes per mutation)
- **RLS coverage** — All 58 tables now have RLS enabled
- **pgTAP testing** — 54 tests covering RLS, indexes, and function correctness