Memory hook: Measure per request and per partition.
Must remember
- Inspect request charge, latency, status/substatus, query metrics and SDK diagnostics. Separate client/network delay from service processing and throttling.
- Target partition keys, use point reads, reduce unnecessary fields and avoid unbounded scans. Index policies trade read efficiency against write/storage cost; composite indexes support particular query shapes.
- Analyze index utilization and query plans before raising throughput. Large items, fan-out queries, excessive indexing and hot tenants can each drive RU consumption differently.
- Azure Monitor metrics/alerts and diagnostic logs in Log Analytics connect service behavior to application SLOs. Monitor end-to-end latency and errors rather than only provisioned RU values.
- Fleet capabilities manage supported groups of accounts, throughput policies and analytics across subscriptions. Fleet-level governance does not eliminate per-account/partition limits or the need to check feature support.
- Load-test representative peak traffic, retries and regional behavior. Reuse SDK clients, respect retry-after guidance and cap concurrency to avoid amplifying a throttling incident.
Choose under exam pressure
| Requirement | Choice and reason |
|---|---|
| One tenant is throttled while the account has spare capacity | Inspect partition distribution and tenant-specific load. |
| A query is expensive despite few returned rows | Inspect scanned data, partition fan-out and index support. |
Traps
- Few returned records do not imply a cheap query.
- More aggressive retries can worsen throttling and latency.
Active recall
1. What does request charge measure?
The RU cost of an operation.
2. Why use SDK diagnostics?
To distinguish retries, routing, client timing and service responses.
3. What does a composite index help?
Supported multi-property query/order patterns that need that index structure.
4. Why monitor p95/p99 latency?
Tail requests may breach user requirements despite a healthy average.
5. What should fleet monitoring complement?
Per-account and per-partition workload diagnosis.