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Generative AI Engineer Associate · Domain 6: Evaluation and Monitoring · 12% of the exam

Task 6.3: Use inference logging to assess deployed RAG application performance; Use inference tables and Agent Monitoring to track a live LLM endpoint; Use AI Gateway (Inference Tables, Usage Tables, and rate limiting) to track an LLM or agent deployed via Agent Framework

Inference tables in Unity Catalog, usage system tables, rate limits, production traces and scorers, and what each tells you about a live endpoint.

Study it

  • Inference tables, usage tables, rate limits and production traces

    Partly covered by: Observability Basics

Sample questions

Try each one before opening the answer. Every option is explained, with the Databricks documentation page that proves it.

Question 1 · choose 2

For a RAG agent that calls a Unity Gateway model service, an engineer must report weekly token use and latency by requester, and debug bad answers by reading the exact prompts and responses. Which TWO data sources should be used? (Choose TWO.)

  1. AThe system.billing.usage table alone
  2. BThe system.ai_gateway.usage system table
  3. CThe AI Search index sync logs
  4. DThe model version's signature
  5. EThe model service's inference table
Show the answer and why
  • AThe system.billing.usage table alone

    Incorrect

    Billing records cost by product and SKU; they hold no prompts, responses or per-request latency.

  • BThe system.ai_gateway.usage system table

    Correct

    The usage table records requester, service, token usage and latency for Unity Gateway services.

  • CThe AI Search index sync logs

    Incorrect

    Index sync history concerns the retriever's data, not the model service's requests.

  • DThe model version's signature

    Incorrect

    A signature describes the model's input and output schema, not traffic.

  • EThe model service's inference table

    Correct

    Inference tables log request and response payloads to a Unity Catalog Delta table for debugging.

Unity Gateway logs usage to system.ai_gateway.usage and, when enabled, request and response payloads to inference tables in Unity Catalog.

Question 2 · choose 1

A model service has a service limit of 1,000 QPM, a default user limit of 60 QPM, a custom limit of 300 QPM for the group batch-jobs, and a custom limit of 500 QPM for the service principal sp-etl, which belongs to batch-jobs. What limit applies to sp-etl?

  1. A300 QPM, because group limits override individual limits
  2. B500 QPM, still subject to the 1,000 QPM service-wide maximum
  3. C60 QPM, because the default user limit applies to every caller of the service
  4. D800 QPM, the sum of the group and the individual limits
Show the answer and why
  • A300 QPM, because group limits override individual limits

    Incorrect

    It is the other way round: individual limits take priority over group limits.

  • B500 QPM, still subject to the 1,000 QPM service-wide maximum

    Correct

    A user or service principal limit takes priority over group limits and overrides the default, while the service limit caps all traffic.

  • C60 QPM, because the default user limit applies to every caller of the service

    Incorrect

    Custom limits override the default user limit.

  • D800 QPM, the sum of the group and the individual limits

    Incorrect

    Limits are not added together; one applicable limit is enforced.

Unity Gateway enforces a service-wide maximum, a default per-user limit and custom limits for users, service principals and groups. Individual custom limits win over group limits, and when both QPM and TPM apply the more restrictive one is enforced.

Question 3 · choose 1

An engineer enables inference tables on a model service and sends a request, but the table is still empty ten minutes later. What is expected?

  1. AThe engineer must create the table first
  2. BRows can take up to an hour to appear
  3. CRows appear only after a manual refresh
  4. DInference tables log only failed requests
Show the answer and why
  • AThe engineer must create the table first

    Incorrect

    Specifying an existing table is not supported; it is created automatically.

  • BRows can take up to an hour to appear

    Correct

    Databricks creates the table after the first request, and rows can take up to an hour to appear.

  • CRows appear only after a manual refresh

    Incorrect

    No manual refresh is documented.

  • DInference tables log only failed requests

    Incorrect

    Logging is not limited to failed requests.

Do not change the inference table's schema or name, or delete it, or logging can stop or the table can become corrupted.

Question 4 · choose 1

A user with CAN QUERY on a model service cannot set up its inference table. Which privilege on the service is required?

  1. AMANAGE on the model service
  2. BCAN QUERY is enough
  3. CSELECT on system.ai_gateway.usage
  4. DWorkspace admin only
Show the answer and why
  • AMANAGE on the model service

    Correct

    Inference tables require MANAGE on the model service, plus CREATE TABLE and USE privileges on the target catalog and schema.

  • BCAN QUERY is enough

    Incorrect

    Querying a service does not allow configuring its logging.

  • CSELECT on system.ai_gateway.usage

    Incorrect

    Reading a system table grants nothing on the service's configuration.

  • DWorkspace admin only

    Incorrect

    The documented requirement is MANAGE on the service, not admin rights.

Both the creator and the modifier of the model service need MANAGE; the table owner is the service creator and ACLs follow Unity Catalog.

Question 5 · choose 1

Security wants to find the callers that still reach Unity Gateway model services with personal access tokens instead of OAuth. Which column of system.ai_gateway.usage answers this directly?

  1. Arequester_type, which separates the two token kinds
  2. Brequest_tags, where the client records its token type
  3. Cuser_agent, which names the token in each request
  4. Dauth_mode, which records PAT or OAUTH per request
Show the answer and why
  • Arequester_type, which separates the two token kinds

    Incorrect

    requester_type says whether the caller is a user, service principal or group, not which credential it used.

  • Brequest_tags, where the client records its token type

    Incorrect

    Request tags hold user-provided values sent with the request header.

  • Cuser_agent, which names the token in each request

    Incorrect

    user_agent identifies the client library, such as an SDK version.

  • Dauth_mode, which records PAT or OAUTH per request

    Correct

    auth_mode holds the Databricks credential type that authenticated each request: a personal access token (PAT) or an OAuth token (OAUTH).

Filtering the usage table on auth_mode = 'PAT' surfaces the traffic that still authenticates with personal access tokens, so the team can move it to OAuth.

Question 6 · choose 1

A data analyst gets permission errors querying system.ai_gateway.usage. Who can read it by default?

  1. AAny user with EXECUTE on a model service
  2. BAny workspace admin, with no other grant
  3. CAccount admins who are also metastore admins
  4. DAll account users, until an admin revokes it
Show the answer and why
  • AAny user with EXECUTE on a model service

    Incorrect

    Service users do not get system table access by default.

  • BAny workspace admin, with no other grant

    Incorrect

    The default requires account and metastore admin roles.

  • CAccount admins who are also metastore admins

    Correct

    Both admin roles are required by default; admins can grant access to system tables to others.

  • DAll account users, until an admin revokes it

    Incorrect

    System tables are restricted by default.

Usage records are typically available within an hour; access is managed through system table grants.

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