Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, that facilitate resource and space efficient analysis of large scale datasets. Methods include obtaining activity data for objects in a dataset. For each data item in the dataset, a hashed parameter having a binary representation is generated using an identifier for the object. A register is identified from among a set of registers based on the hashed parameter. A determination is made that the hashed parameter for the object contributes to an aggregation amount that specifies a number of occurrences of the object in the dataset. Based on this determination, an aggregation amount stored in the register is updated. Based on aggregation amounts stored in the set of registers, a reporting output is generated that provides an aggregate distribution of the objects in the dataset based on the activity data for the objects.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, that facilitate resource and space efficient analysis of large scale datasets. Methods include obtaining activity data for objects in a dataset. For each data item the dataset, a hashed parameter having a binary representation is generated using an identifier for the object. A register is identified from in a set of registers based on the hashed parameter. A determination is made that the hashed, parameter for the object contributes to an aggregation amount that specifies a number of occurrences of the object in the dataset Based on this determination, an aggregation amount stored in the register is updated. Based on aggregation amounts stored in the set of registers, a reporting output is generated that provides an aggregate distribution of the objects in the dataset based on the activity data for the objects.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for an object grouping system that obtains data for multiple sketches that are each stored using a set of registers and are a sampling of objects in a dataset. Each object in the dataset is a member of a digital audience. For each sketch, the system uses an identifier for a first object to generate a hashed parameter. The system determines whether the hashed parameter contributes to describing demographic attributes of the sampling of objects. The system stores demographic attributes of the first object at a register in the set when it determines that the hashed parameter contributes to describing the demographic attributes. The system generates an output that indicates a number of objects in the digital audience that were reached by content directed at the digital audience and demographic attributes for the number of objects.