[JAMES-3997] Netty backpressure for IMAP Fetch

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.8.0, 3.8.1
• Fix Version/s: 3.9.0
• Assignee: Unassigned
• Reporter: René Cordier
• Created: 19/Feb/24 03:46
• Updated: 25/Feb/24 21:59
• Resolved: 25/Feb/24 21:59

Description

Some OOM IMAP issues on a production environment using James have been detected, regarding the method IMAP FETCH.

We seem to do to write out:

channel.writeAndFlush()Unpooled.wrappedBuffer(buffer)); 

without any checks. Making the method using intermediate buffers in a slow network, potentially exploding the memory.

Need to investigate this issue and enhance this processus, maybe by using Netty backpressure instead?

Issue Links

• links to: GitHub Pull Request #2031