I am regularly testing backups to see if they restore ok.

Normally everything goes fine but today it gave an error.

the error itself doesnt say much at all

Database restore error:

And in the log file is error one that made my eye frown..connection failed?

odoo.sql_db: Connection to the database failed odoo.http:
Generating nondb routing werkzeug: 127.0.0.1 - -
[08/Feb/2017 23:37:05] "GET /web/database/manager HTTP/1.1" 200 -

Nothing had changed to the connection or odoo and backups from yesterday load fine!

So i dove into the backup file to find out why it was happening.
deleted the assets folder and tried again.

The database was restored fine!

so it had to be somewhere in the assets... but where and why.

After hours of adding/deleting/trying to see which assets were giving the problem i found out it was a recently created PPT and a generated PDF from that files.

And the PDF file had been used to send as massmail.
The weird thing is that the files dont show anything wrong, they open just fine with whatever program that reads PDF files, so we dont get it why the restore backup functionality is dropping the database connection because of it. What can cause these kind of things?

more better.. how can you avoid it, or pinpoint it more rapidly then hours of trying to find it. (a log message?)

Anyone got an idea?