This is necessary due to data fragmentation caused by the weekly churn of about half a million stale rows in the database and 100-odd user accounts purged.
I've decided to perform a data reset (purge of synced data) instead of trying to defrag the db because:
- Time needed for defragmentation would be restrictive;
- Client-side fragmentation would not be addressed (e.g. having your history synced in thousands of small chunks);
- Stale data from no-longer-synced devices will be purged this way, reducing unnecessary usage of quota and db space on the server.
Also a reminder that this is not a backup service. Storage on the sync server is volatile and temporary and should not be relied on to restore your profile data from as-if it was a backup service.
When sync is back up, you will have to re-sync your data from your browser. This may take some time.