Athena: 31 missing ops, UI polling leak, notebook/session UI #1124

Athena — Service Deep Dive

Audit of services/athena/ and UI in ui/src/routes/athena/+page.svelte.

1. Missing SDK Operations

31 unimplemented (sdk_completeness_test.go#L19):

• Calculations: GetCalculationExecution*
• Sessions: Get/StartSession, GetSessionEndpoint/Status, TerminateSession
• Capacity/Metadata: Get/PutCapacityAssignmentConfiguration, GetCapacityReservation, GetDatabase, GetTableMetadata
• Notebooks: GetNotebookMetadata, Import/UpdateNotebook*
• Executor/Engine: ListExecutors, ListEngineVersions, ListApplicationDPUSizes
• UpdateNamedQuery, UpdatePreparedStatement, GetQueryRuntimeStatistics

2. Missing UI / Dashboard Features

Query editor, workgroups, catalogs, history exist. Missing: notebook editor, session mgmt, capacity reservation, prepared statement mgmt.

3. Goroutine / Resource / Lock Leaks

UI polling leak: setInterval in +page.svelte#L110 has no onDestroy cleanup; navigating away mid-poll leaks timers.

4. Performance Optimizations

1. Results pagination capped at 100 (+page.svelte#L114) — lazy scroll.
2. History uses Promise.allSettled over all executions (#L167) — could overwhelm backend.

Suggested Order

1. Add onDestroy for polling interval
2. Calculation + session APIs
3. Lazy-scroll result pagination
4. Prepared statement + capacity UI