JIRA keys after import continue with "old" keys

Question

A while back, we had JIRA 3 and started a new server with JIRA 6. We imported the old issues we'd need or maybe would come in handy. These keys are very hogh, like 49700 and up.

I don't remember exactly what happened after the import, because we also have "new" ticketnumbers (looks random although we don't delete tickets).

My question is: how can I get JIRA to start over with the keys, beginning at 1?

Thank you!

Vera Henrichs · Answer

Yes, we used a CSV to import all the issues. 
What now?

Nic Brough -Adaptavist- · Answer

Remember not to set a key number lower than the highest numbered issue you already have.  The obvious problem is that eventually the numbers will catch up (so if you have abc-50 in the project and you reset the counter to 1, JIRA will have massive problems when you reach abc-49 and try to create a new issue).  But it also breaks some add-ons and reports in quite unexpected ways.

Phill Fox · Answer

So the migration from 3 to 6 retained the keys (and these were already at 49700 and up)
Is it possible that some of the original issues in 3 were imported from another source? Either an even earlier version of JIRA or maybe by the use of CSV? The same principle would apply there of each key being uniquely assigned and even if the issue is deleted the key would be considered used.