Optimizing Distributed Query Performance | Dataford Interview Questions

How do you optimize query performance in a distributed data environment?

Using the provided tables, write a PostgreSQL query that returns active datasets with at least one failed pipeline run during January 2025.

Output

One row per qualifying dataset with dataset_name, region, failed_runs, and max_duration_seconds
Sort by failed_runs descending, then dataset_name ascending

datasets

Column	Type	Description
dataset_idPK	INT	Unique dataset identifier
dataset_name	VARCHAR(100)	Dataset name
region	VARCHAR(40)	Deployment region
owner_team	VARCHAR(80)	Owning engineering team
is_active	BOOLEAN	Whether the dataset is active

pipeline_runs

Column	Type	Description
run_idPK	INT	Unique pipeline run identifier
dataset_id	INT	Dataset processed by the run
status	VARCHAR(20)	Pipeline run status
started_at	TIMESTAMP	Pipeline start timestamp
duration_seconds	INT	Run duration in seconds

Your question is Optimizing Distributed Query Performance. Start with the requirements and the two tables in the Question tab.

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