Datastore query for running an aggregation over a Query.

Options for a request.

A partition ID identifies a grouping of entities. The grouping is always by project and namespace, however the namespace ID may be empty. A partition ID contains several dimensions: project ID and namespace ID. Partition dimensions: - May be "". - Must be valid UTF-8 bytes. - Must have values that match regex [A-Za-z\d\.\-_]{1,100} If the value of any dimension matches regex __.*__, the partition is reserved/read-only. A reserved/read-only partition ID is forbidden in certain documented contexts. Foreign partition IDs (in which the project ID does not match the context project ID ) are discouraged. Reads and writes of foreign partition IDs may fail if the project is not in an active state.

A GQL query.

Explain options for the query.

The options shared by read requests.