"waitMsAvg" is always 0 for running BQ jobs?

Question

Every time I see my BQ job status through the API, it always returns 0 for waitMsAvg when the job is running.

After the job is finished, then I can see valid numbers for waitMsAvg.

Is it intended behavior, or is it a bug?

How can I see the values when the job is running?

Answer 1

BigQuery query plan provides timing classification for each query stage wherein waitMsAvgis the avg time spent by workers to get scheduled.

You are getting waitMsAvg as 0 because your query is still running. Once the query job completes waitMsAvg will denote the average time worker spent waiting to be scheduled.