In data migration tool config file we have
<direct_document_copy> elements. What values are expected for these tags and what are their purpose?
It is the amount of data processed at one time.
Set bulk_size as
0 and it will be auto-detected for every document. It is better than set bulk_size as a fixed value.
Default value is
0, set it as
1 for better performance.
Set direct_document_copy as
1 will direct copy data from database, but 'source' and 'destination' databases MUST be placed on the same MySQL instance and 'destination' user MUST be granted with 'SELECT' permissions on 'source' database.