History Digests exist to aggregate data from histories and create records in small, task focused tables.
History Digests are still in beta. Please be aware that the functionality described below is still under review and may change.
A primary use for digests is in reporting and generating dashboards. For example, you may want to query several thousand histories and report on the time a particular event occurred within each one. Rather than having to query those histories each time you generate the report, you could create a digest that aggregates the data you need into a new table. The digest could be configured to run on a schedule, adding data from new history records to it.
There's an overview of digests with example usage in the History Digest Overview knowledge base article.
The following functions are used to create and mange the digest tables, columns and data.
Note that when a history is deleted, the row in any digest table it has been digested into is also automatically removed.