codelipenghui opened a new pull request, #20647: URL: https://github.com/apache/pulsar/pull/20647
### Motivation The issue has happened for a topic that has many producers. When many producers connect/disconnect to the topic, the P99 publish latency of the broker will go up to hundreds of ms, which is unacceptable for a messaging system. Each producer add/remove operation will go to MessageDeduplication to update a map for inactive producers regardless of whether message deduplication is enabled or disabled. My first intuitive impression is it shouldn't go to MessageDeduplication if the message deduplication is disabled. But users can enable the message deduplication for an active topic. It might be the reason, but I'm not 100% sure about it. @merlimat Do you happen to have more context about it? And we might also need to look for a solution to avoid any operations to the MessageDeduplication if the message deduplication is disabled. This PR provides a fix without introducing behavior changes, so we will be more confident to cherry-pick to release branches. <img width="1900" alt="image" src="https://github.com/apache/pulsar/assets/12592133/87c22ac2-2af9-4190-a1f2-1872477dd0c4";> [broker_lock_0621_1.html.txt](https://github.com/apache/pulsar/files/11863016/broker_lock_0621_1.html.txt) ### Modifications Use ConcurrentOpenHashMap instead of synchronized HashMap to reduce the contention between IO threads. ### Verifying this change The existing tests can cover the new changes. ### Does this pull request potentially affect one of the following parts: <!-- DO NOT REMOVE THIS SECTION. CHECK THE PROPER BOX ONLY. --> *If the box was checked, please highlight the changes* - [ ] Dependencies (add or upgrade a dependency) - [ ] The public API - [ ] The schema - [ ] The default values of configurations - [ ] The threading model - [ ] The binary protocol - [ ] The REST endpoints - [ ] The admin CLI options - [ ] The metrics - [ ] Anything that affects deployment ### Documentation <!-- DO NOT REMOVE THIS SECTION. CHECK THE PROPER BOX ONLY. --> - [ ] `doc` <!-- Your PR contains doc changes. --> - [ ] `doc-required` <!-- Your PR changes impact docs and you will update later --> - [x] `doc-not-needed` <!-- Your PR changes do not impact docs --> - [ ] `doc-complete` <!-- Docs have been already added --> -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
