The HistoryBackend consists of a number of components:
HistoryDatabase
Stores past 3 months of history
- URLDatabase (stores a list of URLs)
- DownloadDatabase (stores a list of downloads)
- VisitDatabase (stores a list of visits for the URLs)
- VisitSegmentDatabase (stores groups of URLs for the most visited view)
ArchivedDatabase
- Stores history older than 3 months
- URLDatabase (stores a list of URLs)
- DownloadDatabase (stores a list of downloads)
- VisitDatabase (stores a list of visits for the URLs)
(this does not store visit segments as they expire after 3 months)
TextDatabaseManager
- Manages multiple text database for different times
- TextDatabase (represents a single month of full-text index)
ExpireHistoryBackend
- Manages moving objects from HistoryDatabase to the ArchivedDatabase and deleting
| Static Constant | Value | |
|---|---|---|
| Segment Data Retention | 90 days | How long Chrome keeps segment data for in days. Currently 3 months. |
| Commit Interval Seconds | 10 seconds | How long Chrome waits to do a commit, so that things are batched together. |
| Favicon Refetch Days | 7 days | The amount of time before Chrome re-fetches the favicon. |
| Archive Days Threshold | 90 days | The number of days old a history entry can be before it is considered "old" and is archived. |