| # Pivot Tables |
| |
| Pivot Tables are a way to summarize and aggregate information about selected |
| slices in a configurable way. It is available in canary and autopush channels by |
| default, and can be enabled in stable by toggling a corresponding flag |
| (Support > Flags > Pivot tables V2). |
| |
| To create a pivot table, you need to select a timeline area that contains |
| slices. The table will then show an aggregation of the selected slices. |
| |
| ## Conceptual model |
| |
| Pivot tables have two types of columns: pivots and aggregations. Conceptually, |
| the UI requests all the data from columns of both types and then computes |
| aggregate values for aggregation columns for every distinct tuple of pivot |
| column values. |
| |
| Pivots are hierarchical, and the aggregate values are also computed for all the |
| prefixes of pivot column values. For example, if you select process name, |
| category, and event name (in that order) as pivots and have duration sum as the |
| only aggregation columns, the following aggregate values will be computed: |
| |
| * Total duration for each process |
| * Total duration for each process and category |
| * Total duration for each process, category, and event name |
| |
| The table rows are appropriately nested in the UI, from more general to more |
| specific. Portions of the table can be collapsed and expanded. |
| |
| ## Working with pivot table |
| |
| Pivot tables can be configured using dropdown menus in the table header cells. |
| These can be used to: |
| |
| * Add and remove pivots |
| * Add and remove aggregations |
| * Change aggregation functions |
| * Sort by aggregation columns |
