Populating a field in all existing issues with the value of another field

Question

What would be the most straightforward way to populate a new field in 10000+ existing issues with the value of another field? For example, a new field called Name is available, and we want it to show the same value as an existing field called "Email".

Jobin Kuruvilla [Adaptavist] · Accepted Answer

Might be better off doing it in the database. You can write a script to update customfieldvalue table.

Make sure you have a good backup and do it when JIRA is offline. Also, you will have to reindex after the restart.

Another option is to write a script/servlet that copies the values. Less risk but might take more time.