Flex slots and bytes billed

Google Cloud Data Analytics
1

Hey,

I’ve been testing flex slots in my company to bring the costs of scheduled queries down and have managed to successfully create a commitment, reservation and assignment to my project through BQ UI using SQL as shown here: https://cloud.google.com/bigquery/docs/reservations-get-started

While the flex slots were active I ran a query in BQ UI that processed 117.7 GB. In the “Job Information” section of the results, I can see that the query was executed under the reservation I have created, which seems OK.

However, when I wanted to check what I was billed for the query, I ran the following query (with relevant WHERE statement) to get the information about my job:

SELECT * FROM region-us.INFORMATION_SCHEMA.JOBS_BY_PROJECT

I was surprised to see that value in “total_bytes_billed” column is not 0 - instead it’s basically the same as the value in “total_bytes_processed”, while the value in “reservation_id” column matches the one I saw in Job Description earlier.

I expected “total_bytes_billed” value to be 0 since the query was run under a flex slot reservation.

Could someone please answer the following two questions:

  1. Does reservation_id indicate that the query did indeed run under a flex slot reservation and that the bytes processed will not be billed as if the query was on-demand (even though bytes billed value from information_schema is not 0)?

  2. Is there anything else I can do to confirm that the job has been run under a reservation and the query cost will not be charged per byte?

Best regards,

Klemen

2

Note - after several hours of searching I finally found the answer to 1.:

https://cloud.google.com/bigquery/docs/information-schema-jobs

According to the information schema definition the bytes billed is merely informational:

“If the project is configured to use flat-rate pricing, then you are not billed for bytes and this field is informational only.”

I still however am curious about question 2.

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