Group By Semantics - Pruning and Ordering of Chart Results

In its basic form, Group-by is a mechanism to categorize events for aggregation. Example: we want to count the number of events by country:

For more information on group-by visualization in Event Segmentation charts, please see this article: Build charts in Amplitude: add events and user segments

Table of Contents

• Pruning
• Group Ordering

Pruning

In order to maintain performance at large scale, we set a maximum limit on the number of groups a query result can return. When this limit is exceeded, we keep the top groups and prune the rest from the query result. The top groups are determined by the ordering information below.

If you are doing a single group by in the event segmentation chart, these results may be limited to 100 group by results. If you are doing a double group by, these results may be limited to 500 group by results in which each group by value pair is counted as 1 result.

Group Ordering

The top groups that are surfaced in the Breakdown Table for each Event Segmentation metric are based on the following:

Note: For formulas, the ordering in the above table will only be used if every metric in the formula uses the same ordering. Otherwise, the default formulas ordering will be used.