Google offers two different types of queries. Interactive queries are BigQuery's most costly queries and will run as soon as possible when initiated. Users using Google's on-demand pricing will be subject to Google's concurrent query limits. These users can run 50 concurrent interactive queries and users can run 6 concurrent queries containing user-defined functions.
Batch queries are less costly and do not count against concurrent query limits. These queries are run when resources are available; therefore, these queries might not run as soon as possible when initiated. If a query does not run within 24 hours, its priority is set to interactive.