According to the BigQuery client API reference (using the Java API as example), there is a "quotaUser" parameter which can be set on inserting a new Job on BigQuery:
Available to use for quota purposes for server-side applications. Can be any arbitrary string assigned to a user, but should not exceed 40 characters. Overrides userIp if both are provided.
.. and a "userIp" parameter:
IP address of the site where the request originates. Use this if you want to enforce per-user limits.
... but there is no mention to that parameters at the BigQuery Rest API reference.
How do those parameters work? Do they transfer the 20-concurrent-jobs quota to the user instead of my server? Or any other quota defined here?
Thanks.
These parameters are provided by the google APIs service that BigQuery uses, but are not actually used by BigQuery. You should ignore these parameters when using BigQuery. Most BigQuery queries are applied at the Project level, which would not be affected anyway.