poorbarcode opened a new pull request, #19344: URL: https://github.com/apache/pulsar/pull/19344
### Motivation When we call `pulsar-admin topics stats`, we calculate the backlog size of each subscription; during this process, managed-ledger's synchronization lock is used(see `code-1` below), which affects the sending of messages. If there are `N` subscriptions under this topic, then will acquire this synchronization lock N times , which magnifies the impact. #### Code-1: synchronization in ManagedLedger https://github.com/apache/pulsar/blob/644be5fdd6d080accffd72229b2e21e35a27d722/managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java#L1269-L1283 ### Modifications <strong>(Highlight)</strong>No matter how many subscriptions there are, the synchronization lock in the managed ledger is only acquired once when `pulsar-admin topics stats` is called. - Take a snapshot of the Managed ledger (which would require a lock to ensure that multiple variables match), and then use the snapshot to calculate backlog size for each subscription(this will incur excess memory). ### Documentation <!-- DO NOT REMOVE THIS SECTION. CHECK THE PROPER BOX ONLY. --> - [ ] `doc` <!-- Your PR contains doc changes. Please attach the local preview screenshots (run `sh start.sh` at `pulsar/site2/website`) to your PR description, or else your PR might not get merged. --> - [ ] `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 --> ### Matching PR in forked repository PR in forked repository: - https://github.com/poorbarcode/pulsar/pull/55 -- 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]
