Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for analyzing data. In one aspect, a mixer server receives a request for a visualization of television reporting data, translates the request for the visualization of the television reporting data into sharded requests, and provides each sharded request to a respective shard server. Each shard server processes a respective proper subset of the television reporting data to generate data representing the visualization, and provides the data representing the visualization to the mixer server. The mixer server aggregates the data representing the visualizations received from each of the shard servers, and provides the aggregated data representing the visualization as a response to the request for the visualization of the television reporting data.