BigQuery Query Plan

In BigQuery, a query plan is provided for executed queries. Deciphering query plans can lead to further query optimization.

Let's execute the following SQL in BigQuery:

SELECT
    subject AS subject,
    COUNT(*) AS num_duplicates
FROM
    `bigquery-public-data.github_repos.commits`
GROUP BY
    subject
ORDER BY
    num_duplicates DESC
LIMIT 10
;

By clicking the "EXECUTION DETAILS" button, you can review the query plan.

BQ Visualizer

Using the BQ Visualizer, you can visualize SQL execution results, including BigQuery query plans and Slot usage.

Visit https://bqvisualiser.appspot.com/ and click the "Login" button to perform authentication.

After authentication, enter the project and job ID, then click the "GET" button.

You can now review the visualized query plan.

References

https://cloud.google.com/bigquery/docs/query-plan-explanation
https://bqvisualiser.appspot.com/