Where does the JIRA mail handler store in-reply-to header?

[Shun Hirayanagi]

URL below says the JIRA mail handler refers to in-reply-to mail header to determine which issue JIRA should add an email as a comment to.
https://confluence.atlassian.com/cloud/creating-issues-and-comments-from-email-687219897

My question is where JIRA stores mail header information. (maybe in database?)
I want to know this to search missing emails which occasionally happen due to the header, like https://confluence.atlassian.com/display/JIRAKB/Comment+Handler+Is+Unable+to+Identify+Issue

[Piotr Klimkowski · Accepted solution]

NotificationInstance table.

Please note that comment mail handler first checks mail subject for any issue key, then checks the in-reply-to header and finally the References header in this table. 

 https://jira.atlassian.com/browse/JRA-11181

[Shun Hirayanagi]

Thanks a lot!

[Bryan Bai]

it looks like JIRA stop using this table after version 6.

NotificationInstance table

how JIRA track the Message-ID now ?

[Bryan Bai]

and according to this open ticket, the In-Reply-To check of incoming email function also broken:

https://jira.atlassian.com/browse/JRASERVER-43397