4596. Optimizer Engineering: query-plan approval — Reduce cost/latency while preserving semantics. — subscription billing — Go database/sql

DBMS Published 30 Sept 2026 Updated 30 Sept 2026 0 Views Verified

Scenario: A subscription billing application must handle query-plan approval. Reduce cost/latency while preserving semantics. Explain the invariant, SQL strategy, transaction/locking behavior, failure handling, observability and test plan. Use MySQL 8-oriented syntax where applicable.

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Answer & Explanation

4 Answers

Verified Correct Answer

Option 1: Use a parameterized, transaction-aware MySQL 8 implementation for query-plan app

Use a parameterized, transaction-aware MySQL 8 implementation for query-plan approval, validate the invariant, and explicitly test concurrency, retries and recovery.

Additional Explanation

Correctness depends on explicit invariants, safe SQL, transaction/concurrency handling and verification.

Verified

Option 2: Use unparameterized dynamic SQL and rely only on application-side validation for

Use unparameterized dynamic SQL and rely only on application-side validation for query-plan approval.

Additional Explanation

Correctness depends on explicit invariants, safe SQL, transaction/concurrency handling and verification.

Verified

Option 3: Disable database protections and repair inconsistent rows manually after query-p

Disable database protections and repair inconsistent rows manually after query-plan approval runs.

Additional Explanation

Correctness depends on explicit invariants, safe SQL, transaction/concurrency handling and verification.

Verified

Option 4: Run query-plan approval without defining transaction boundaries, retry behavior,

Run query-plan approval without defining transaction boundaries, retry behavior, or production validation.

Additional Explanation

Correctness depends on explicit invariants, safe SQL, transaction/concurrency handling and verification.