[JAMES-2805] Top level implementation of the DeletedMessageVault

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.4.0
• Assignee: Unassigned
• Reporter: Benoit Tellier
• Created: 24/Jun/19 09:49
• Updated: 02/Aug/19 07:06
• Resolved: 02/Aug/19 07:05

Description

While working on the deletedMessageVault, we targeted in MAILBOX-381 a first implementation on top of MailRepositories

That decision was unfortunate as then one can browse the content of the deletedMessageVault vault through webAdmin.

Thus we decided to implement DeletedMessageVault as a separate component.

That component has the following considerations:

• Should have a low storage cost
• Cold storage and delays upon reads are acceptable as one does not expect a restore/export to be fast
• Find an efficient way to implement retention (deleting too old emails) without a full scan

We decided to provide an implementation above the blobStore and a metaData store (cassandra)

Retention will be implemented with object storage buckets (one month = 1 bucket). We could then simply delete a bucket when all the mails it contains are older than the retention period.

Querying the deleteMessageVault will first be done with a full scan. Later enhancement can be done by providing a per-bucket (immutable) Lucene index - once the bucket is no longer the latest one.