Eventhouse — Parity gap (validator verdict 2026-05-26)

Grade: C (one BLOCKER + multiple MAJORs)

Validator: v2 4-phase live-browser + source-code review.

Loom URL: https://loom-console-fvbbctd4eehqbkcs.b02.azurefd.net/items/eventhouse/79e38fe3-7cd2-47ee-b0ea-7a80bc999891

Loom screenshot: temp/parity/eventhouse-loom.png (full-page; captured during a brief render window — note the Loom tab-strip carousel rapidly cycles back to other tabs, but the editor body itself was probed via direct DOM evaluation + source-code review). Reference UX from docs/fiab/eventhouse-parity-spec.md.

Phase 1 — Fabric reference (from spec)

System overview pane (storage metrics, system resources, top users, ingestion rate, top queried + ingested DBs, "What's new"). Per-database management: Tables view as Cards or List with per-table metadata (compressed size, last ingestion, OneLake availability toggle, row count, original size, retention, caching policy, creation date, creator). Data preview (top records). Query insights pane (duration percentiles, cache hit, top queries by metric). OneLake integration (availability sync seconds, mirrored schema, query acceleration policies, OneLake cache vs standard, sync status). NL2KQL Copilot.

Phase 2 — Loom under test (live)

Card grid showing KQL databases under the cluster. Each card shows database name only (plus optional prettyName, plus a default badge when matching defaultDatabase). One toolbar: Refresh + "New KQL database" button (opens a Dialog with a name field). That's the entire editor.

Source confirmation: apps/fiab-console/lib/editors/phase3-editors.tsx lines 161-270. State shape: { ok, cluster, defaultDatabase, databases:[{name, prettyName, persistentStorage}], error }.

Backend probe (live): - GET /api/items/eventhouse/79e38fe3-… → 200 with real cluster URI https://adx-csa-loom-shared.eastus2.kusto.windows.net and one DB loomdb-default. - POST /api/items/eventhouse/79e38fe3-…/database {name:"parity_test_db"} → 200 with real ARM resource ID /subscriptions/363ef5d1-…/Microsoft.Kusto/Clusters/adx-csa-loom-shared/Databases/parity_test_db and provisioningState: Creating. Real ARM provisioning.

Phase 3 — Side-by-side gap matrix

Fabric element	Loom	Severity
System overview pane (storage metrics, ingestion rate, top users)	Missing	BLOCKER for parity (this is the default Fabric landing pane for an Eventhouse)
List of child KQL databases	Present — card grid with name + default badge	(positive)
Create new KQL database dialog	Present — name input → real ARM POST	(positive, A-grade plumbing)
Per-database rich metadata (compressed size, retention, caching, OneLake availability, row count, original size, creation date, creator)	Missing — only name shown on card	MAJOR
Per-table data preview (top records inline)	Missing	MAJOR
OneLake availability toggle per table (ADX .alter table ... policy onelake_availability)	Missing — ribbon label only, no action	MAJOR
Query insights pane (duration percentiles, cache hit, top queries)	Missing	MAJOR
NL2KQL Copilot inline	Missing	MAJOR
Capacity metrics integration (CU usage, billing)	Missing	MINOR (admin Azure resources page covers some)
Materialized views / Functions / Data streams / Shortcuts sub-trees	Missing	MAJOR
Cards or List layout toggle	Missing	MINOR
Ribbon tabs (Home with New / Query / Manage groups)	Present	(positive)
Honest MessageBar for missing OneLake / capacity infra	Missing — buttons appear functional but do nothing	MAJOR (per no-vaporware.md)

Phase 4 — Functional click-every-button verification

Loom control	Result
GET /api/items/eventhouse/{id}	200, real cluster + DB list
New KQL database dialog → Create	POST /api/items/eventhouse/{id}/database → 200, real ARM provisioning. PRIMARY ACTION WORKS
Refresh button	Re-fetches the cluster state
Ribbon: New KQL database / New dashboard / Query with code / Get data / Data policies / OneLake availability	No-op — labels render but no click handlers bound (ribbon definitions are static labels). BROKEN (silently dead)
Database card click	No detail pane opens; just visual hover effect. BROKEN-ish (Fabric clicks open the per-DB view)

Verdict

C-grade. Real backend, real ARM provisioning works (good plumbing on the narrow primary path). But: - No system overview pane → BLOCKER for full parity - Per-table management (metadata, OneLake toggle, query insights) entirely missing - Ribbon buttons silently dead → BROKEN per no-vaporware.md - No drill-down from DB card to its tables/views/functions

Catalog spec correctly identified gaps 1-6. Backend exists; UI work to surface metrics + policy controls remains.

Required for ≥ B grade

1. System Overview pane on the editor body when no DB is selected, with ADX .show cluster details + diagnostic-metric reads for ingestion rate / top queries. Cite the bicep that deploys diagnostic settings.
2. Clicking a DB card drills into a per-DB view showing tables (with each table's metadata: compressed size, retention, OneLake toggle, row count).
3. Wire the ribbon buttons:
4. New KQL database → already-working dialog
5. New dashboard → spawns a kql-dashboard item in the same workspace
6. Query with code → opens a kql-queryset
7. Get data → opens the GetData workflow (ADX .ingest + sample data)
8. Data policies → opens an ADX policy editor (retention/caching/update)
9. OneLake availability → toggle that issues .alter table T policy onelake_availability
10. For any of the above that aren't yet deployed in the Loom instance, surface the honest MessageBar gate per no-vaporware.md.

Estimated effort: 2-3 sessions for the UI work (backend already exists per catalog).

Evidence

• Live API calls (validator run):
• GET /api/items/eventhouse/79e38fe3-… → 200 (real cluster URI, real DB list)
• POST .../database → 200 (real ARM provisioning, resource ID returned)
• Source code: apps/fiab-console/lib/editors/phase3-editors.tsx lines 144-270.
• Screenshot: temp/parity/eventhouse-loom.png.