Issue Summary

Confluence experiences sudden thread pool exhaustion after running stably for a period of time.

• Occurrence & Timing: The issue typically occurs around 04:30 JST. There is currently no evidence linking this to scheduled jobs.

• Impact: When the issue occurs, the number of stuck threads increases rapidly until the HTTP thread pool is completely exhausted, rendering Confluence inaccessible to end users.

• Recovery & Recurrence: Confluence cannot self-recover from this state; a restart is required as a temporary workaround. However, the issue tends to recur periodically (approximately once a month) following a restart.

• Other information:   In thread dump , looks all stuck thread are waiting for a lock object, but owner of the lock object is not output. Sometimes , dead locks show in the thread dump.

Steps to Reproduce

While the issue is currently difficult to reproduce in-house, it consistently reproduces in the customer's environment roughly a month since a restart.

Expected Results

Confluence should maintain stable, normal operation continuously over time without requiring periodic restarts.

Actual Results

Confluence exhausts its thread pool after running continuously for an extended period

Workaround

Currently there is no known workaround for this behavior.

As a temporary mitigation, the customer can schedule periodic restarts (e.g., weekly) to prevent unexpected outages.