COST-CAT-001 — Load table-detail tabs on demand
| Field | Value |
|---|---|
| Status | Open finding; source-verified and live failures observed |
| Severity | High |
| Affected surface | Catalog table Overview, Sample, History, Quality, Permissions, and Lineage |
| Implementation issue | oqullus #533 |
| Code-change repository | sparqd/oqullus |
Where the problem appears
Open a table and remain on Overview while recording network and Trino activity.
Concrete observed case
A single table selection can start columns, sample, Delta history, two DataHub metadata reads, and two DQ reads. Sample, History, and Quality work begins even when the user never opens those tabs.
Expected condition
Overview loads only its required summary. Each secondary tab loads once on first activation, owns loading/error/retry state, cancels stale work after navigation, and supports an explicit refresh.
Cause and evidence
- At least seven logical reads are initiated from one table open.
- Several reads execute queries or reach independent services.
- Observed DQ failures were generated while the user remained on Overview.
Why it matters
Unrequested work consumes Trino and service capacity, increases latency and query-history noise, and fans one dependency failure into the whole table page.
Existing controls and workarounds
No user action reliably prevents the eager requests. Avoid repeatedly opening tables while affected dependencies are failing.
Alternatives considered
- Recommended: per-tab lazy loading with canonical-identity cache and cancellation.
- Prefetch after Overview becomes idle — possible only with explicit budgets and low-priority cancellation.
- Keep eager loading for faster tab switches — rejected until its cost and failure isolation are bounded.
Component involvement
- Oqullus owns activation, cancellation, state, and refresh.
- BFF endpoints must support bounded, independently observable operations.
- Operations owns query and dependency telemetry.
Reproduction and verification
Follow CAT-S020. Record the visible state, request outcome, effective identity, and recovery behavior relevant to this finding.
Resolution conditions
Close when Overview triggers only documented required reads, unopened tabs create no work, navigation cancels stale requests, and each tab independently handles loading, failure, retry, and refresh.
Validation and blockers
Oqullus is primary; BFF and operations validate request and query behavior.