I tried updating my emonbase today and after first getting a could not connect to database error, I rebooted and found that I had no historical data in the myelectric app, but there is 96MB of data in the feeds page.
I tried updating the database, but it says it is up to date. After tried to update the emonbase itself, it still says it is on version 9.8.8, which is what it was before trying to update.
The update log shows that the update was last run on 24th Aug 2017. Is this correct? Do you see the update log run when you clicked emonPi update? Could you try and run update again?