Inspect its profile, scanned data, joins, spills and queueing before changing warehouse size.
Illustrative scenario
A report slows after a new join.
Explain your reasoning
Apply the answer to this scenario: Is the problem execution time or waiting time? State your assumptions, the expected outcome and how you would check it before changing a real system.
Measure idle and active usage, tune suspension and workload patterns, then test sizing against elapsed time and credits.
Illustrative scenario
A warehouse stays active between infrequent queries.
Explain your reasoning
Apply the answer to this scenario: Could frequent restarts reduce cache benefits? State your assumptions, the expected outcome and how you would check it before changing a real system.
Choose a deterministic source version per key and reject unresolved ties before writing.
Illustrative scenario
Two price updates match one target product.
Explain your reasoning
Apply the answer to this scenario: Why is disabling the error a poor default? State your assumptions, the expected outcome and how you would check it before changing a real system.
Unmatched duplicate source rows may each be eligible for insertion; deduplication and key checks remain necessary.
Illustrative scenario
An empty target receives a repeated source key.
Explain your reasoning
Apply the answer to this scenario: How would you test this before production? State your assumptions, the expected outcome and how you would check it before changing a real system.
Use transactional processing with correct change semantics and understand when its offset advances.
Illustrative scenario
A downstream update consumes a stream and writes a target.
Explain your reasoning
Apply the answer to this scenario: What happens if the transaction rolls back? State your assumptions, the expected outcome and how you would check it before changing a real system.
Required change history can become unavailable when the stream is not consumed within relevant retention limits.
Illustrative scenario
A consumer is paused too long.
Explain your reasoning
Apply the answer to this scenario: How will you reinitialize and reconcile? State your assumptions, the expected outcome and how you would check it before changing a real system.
A scheduled transformation stops after a role change.
Explain your reasoning
Apply the answer to this scenario: How do you rerun without duplicate effects? State your assumptions, the expected outcome and how you would check it before changing a real system.
Check stage contents, file eligibility, event delivery, pipe status and load history.
Illustrative scenario
A file exists but no target rows appear.
Explain your reasoning
Apply the answer to this scenario: Was the file already considered loaded? State your assumptions, the expected outcome and how you would check it before changing a real system.
Design roles by responsibility, grant minimal object access and review inheritance and ownership.
Illustrative scenario
A service can load raw data but must not read sensitive curated tables.
Explain your reasoning
Apply the answer to this scenario: How are future objects governed? State your assumptions, the expected outcome and how you would check it before changing a real system.
Compare representative pruning and query profiles with maintenance cost before and after a controlled change.
Illustrative scenario
A large table has repeated selective range queries.
Explain your reasoning
Apply the answer to this scenario: What happens when query patterns change? State your assumptions, the expected outcome and how you would check it before changing a real system.
Its scope is not every possible account charge. Understand the resources it controls before treating it as a total spending cap.
Illustrative scenario
A team monitors user-managed warehouse credits.
Explain your reasoning
Apply the answer to this scenario: Which serverless costs need separate monitoring? State your assumptions, the expected outcome and how you would check it before changing a real system.
Distinguish persisted query results from warehouse data caching and test without assuming every run is a cold run.
Illustrative scenario
A repeated benchmark appears dramatically faster.
Explain your reasoning
Apply the answer to this scenario: Which changed conditions prevent result reuse? State your assumptions, the expected outcome and how you would check it before changing a real system.
Use explicit effective boundaries, a stable business key and tests for one current version and non-overlapping history.
Illustrative scenario
A customer category changes.
Explain your reasoning
Apply the answer to this scenario: How are late historical corrections handled? State your assumptions, the expected outcome and how you would check it before changing a real system.
Inspect refresh history, dependency chains, target lag and refresh cost rather than assuming scheduled intent equals actual freshness.
Illustrative scenario
A downstream table lags behind its source.
Explain your reasoning
Apply the answer to this scenario: Which upstream refresh first fell behind? State your assumptions, the expected outcome and how you would check it before changing a real system.
Validate required paths and types, quarantine invalid records and version important transformations.
Illustrative scenario
A JSON amount changes from number to nested object.
Explain your reasoning
Apply the answer to this scenario: How will dashboards detect the change? State your assumptions, the expected outcome and how you would check it before changing a real system.
Benchmark representative workloads and concurrency, balancing completion time, spill behaviour and cost.
Illustrative scenario
A batch misses its deadline.
Explain your reasoning
Apply the answer to this scenario: Would query optimization help more than extra compute? State your assumptions, the expected outcome and how you would check it before changing a real system.
Common follow-up
Would query optimization help more than extra compute?
They address eligible concurrency needs rather than automatically speeding one individual query.
Illustrative scenario
Many analysts submit queries at the same time.
Explain your reasoning
Apply the answer to this scenario: Is queueing actually the bottleneck? State your assumptions, the expected outcome and how you would check it before changing a real system.
Exercise documented recovery paths with disposable data, including retention and permissions.
Illustrative scenario
An accidental delete must be recovered.
Explain your reasoning
Apply the answer to this scenario: How will you avoid overwriting valid later changes? State your assumptions, the expected outcome and how you would check it before changing a real system.
Common follow-up
How will you avoid overwriting valid later changes?
Use supported integrations and scoped cloud permissions instead of embedding long-lived secrets in scripts.
Illustrative scenario
A loader reads one cloud-storage prefix.
Explain your reasoning
Apply the answer to this scenario: How are changes to the external trust policy reviewed? State your assumptions, the expected outcome and how you would check it before changing a real system.
Common follow-up
How are changes to the external trust policy reviewed?
Compare schemas, counts, business aggregates, edge-case semantics and representative query behaviour.
Illustrative scenario
An Oracle reporting workload moves to Snowflake.
Explain your reasoning
Apply the answer to this scenario: Which null, date and numeric differences need explicit tests? State your assumptions, the expected outcome and how you would check it before changing a real system.
Common follow-up
Which null, date and numeric differences need explicit tests?