[improve][broker]Increase the number of delayed messages sent whose delay time exceeds the TTL statistical metric

[zjxxzjwang]

Motivation

Currently, Pulsar Broker lacks a metric to track instances where delayed messages exceed their TTL. This results in messages set with delayed delivery times exceeding the TTL expiring before being consumed by users, with no mechanism to detect this occurrence. Consequently, there is a significant risk of message loss.

Modifications

1. Add a new member variable Rate exceedTTLDelayMessage = new Rate() to PersistentTopic to track the number of delayed messages exceeding the TTL.
2. Within the message sending logic of handleSend, add a check specifically for delayed messages whose delay time exceeds the TTL. If exceeded, call exceedTTLDelayMessage.recordEvent().
3. In TopicStatsImpl, add the exceedTTLDelayMessages variable to retrieve and display the count of delayed messages exceeding the TTL.

Documentation

• [ ] doc
• [ ] doc-required
• [x] doc-not-needed
• [ ] doc-complete