For example, the sippy backup script has been failing due to:

time="2024-04-02T07:05:07.594Z" level=info msg="Refresh complete"
time="2024-04-02T07:05:07.594Z" level=warning msg="1 errors were encountered while loading database:"
time="2024-04-02T07:05:07.594Z" level=error msg="loader \"prow\" returned error: error parsing prowjob from bigquery: bigquery: NULL cannot be assigned to field `StartTime` of type Time"

Our bigquery schema for the jobs table for 'prowjob_start' (and 'prowjob_completion') allows for NULL timestamp (i.e., the type is DATETIME NULLABLE).

But our bigqueryProwJobRun struct does not allow for a NULL timestamp (type is time.Time).

The offending job (which has a NULL start time) was already deleted which circumvented the error in the sippy backup script and allowed it to finish.

We'd like to fix our sippy code to avoid this problem and also avoid adding adding jobs that have null start times.