What would lead to an “Unknown object in backup file” problem when restoring a backup of a MySQL database?

Question

Unfortunately, the problem is not more specific than that. I've found a few examples of people reporting similar problems by doing a Google search , but I can't find the part of the restore that is actually causing the problem, which might help me track it down on my own.

Suggestions for either resolving this problem or being able to track down the root cause would be appreciated.

Answer 1

ANOTHER FIX

I also had this problem! The answers online didn't seem to help (max_allowed_packet and others)

Here's what fixed mine:

Instead of running the Restore function, I imported through MySQL Migration Toolkit (installed with GUI Tools on Windows).

The Migration Toolkit also failed, but had descriptive errors in the Log on the final page. In my case, it was a few incorrect Date fields in my data (usually "0000-00-00") that wouldn't migrate correctly.

Fixing these dates in my tables solved the Restore problem.

Hope this helps somebody else out there.

Answer 2

There's one bug logged at bugs.mysql.com that references the error you describe:

" Bug #37253 Unable to restore backup file containing BLOBs "

The solution described in that bug is to increase the max_allowed_packet in the MySQL server configuration. The user confirmed that raising the value to 100M allowed him to restore his database.

Answer 3

I have had something similar in the past- it has something to do with how it was backed up. I think some applications put invalid comments in the backup files which cause errors.

My suggestion- if you are stuck trying to restore those files- is to incrementally start backing up from sections of the backup file and find what is causing the problems- which from what I recall the case for me was that they were some text in the file that was inconsequential to remove.