Batch deleting nodes breaks database On my Drupal site, I have about 100 nodes that need deleting. I have deleted them via Views Bulk Operations. 

When I do this, if I make a backup of my site MySQL database and then try to restore it via PHP My Admin, I get the following error:

INSERT INTO `cache_form` (`cid`, `data`, `expire`, `created`, `serialized`) VALUES
('form_state_form-0ry4vXadnLIroZBOuRNpM4WJWgNm0HNVumQ1bNHLEu4', 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[...]
MySQL said: Documentation

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 2 


The error has been caused by deleting the nodes. If I go to an earlier back-up before the nodes were deleted, it works fine. However, everytime I delete the nodes, this error comes back.

How can I delete the nodes without the database becoming corrupt. I clear the cache after deletion and before backing up, but the problem still occurs.

Interestingly after deleting nodes, the size of the databse jumps from 16MB to 80MB. So I am not sure if the deletion is putting some bad data in the database.
You need to increase max_allowed_packets in my.cnf file. to insert big data from cache tables. The best practice to avoid this is, never export cache prefixed tables data.