While running the data migration tool. I constantly came across the SQLSTATE error message. It would read: SQLSTATE: Integrity constraint violation: 1062 Duplicate entry ‘611516’ for key ‘PRIMARY’. To fix, I had to look for duplicate entries found in Magento 2 compared to Magento 1. Much of the duplicate entries were found in the database under the table report_event and customer_visitor.
To bypass the error message I had to delete the duplicate entry found in the Magento 2 database. The only problem is the duplicate entry message kept on reappearing with a different duplicate entry every time I ran the data migration tool. It was happening for the logged files of Magento. Something I figured I could live without and ignore migrating to the Magento 2 store.
So I deleted it from the data migration tool by going to the config.xml file and removing the log script. This is what I removed:
<step title="Log Step"> <integrity>Migration\Step\Log\Integrity</integrity> <data>Migration\Step\Log\Data</data> <volume>Migration\Step\Log\Volume</volume> </step>
After I removed the above log step I continued with the data migration tool without any more duplicate errors. And everything was migrated from Magento 1 to Magento 2.