Template:Longitudinal data intro

The longitudinal dataset is a summary of main pings. In general, you should prefer using the longitudinal set to main_summary unless there are extenuating circumstances.

In particular, the longitudinal dataset:

• makes it easy to report profile level metrics by grouping data for the same client-id in the same row
• samples to 1% of all recent profiles, which will reduce query computation time and save resources

As discussed in the Longitudinal Data Set Example Notebook:

The longitudinal dataset is logically organized as a table where rows represent profiles and columns the various metrics (e.g. startup time). Each field of the table contains a list of values, one per Telemetry submission received for that profile. [...]

The current version of the longitudinal dataset has been build with all main pings received from 1% of profiles across all channels with [...] up to 180 days of data.