Reason for the deletion of some tickets happened from database of Jira and ticket Id is there in UI.

[Asiya Shajahan]

Jira ticket id is visible in UI and can't view it. When we checked on database the ticket id is not there, assuming it is deleted. There is no auto deletion scripts written. What would be the reason for sudden deletion of some tickets from database?

[Nic Brough -Adaptavist-]

Stop looking in the database, it doesn't work the way you think it does.

Do the issues appear to have vanished in the UI?  Do they vanish if you edit or transition them?  If not, then there's nothing wrong and they have not been deleted.

[Asiya Shajahan]

yes. It won't deleted from DB. But some index file got corrupted and not able to view the tickets. Can I resolve it by restarting the server or Is there any other way? 

what could be the correct reason for getting index failure exceptions.

[Nic Brough -Adaptavist-]

The usual way to corrupt an index is by amending the database.

Do the issues appear to have vanished in the UI?  Do they vanish if you edit or transition them?  If not, then there's nothing wrong and they have not been deleted.