poorbarcode opened a new pull request, #25293: URL: https://github.com/apache/pulsar/pull/25293
### Motivation https://github.com/apache/pulsar/pull/23062 improved the behaviour of initialising the Transaction Buffer: Synchronise the reader creation, read loop and the following process on its result. Maintain only one reader for each namespace. The reader is now not closed unless there is no snapshot read request in 1 minute. However, [SimpleCache](https://github.com/apache/pulsar/pull/23062/changes#diff-874612f5aa0d34f1df3c8d48bd8d4a4b28dc826a12fd08c45e1a62e10f6b5182) is a global lock, and the lock force is too strong, causing all `pulsar-transaction-snapshot-recover` threads to get stuck in the creation of the first reader. When system resources are insufficient, the problem will be magnified infinitely <img width="1515" height="965" alt="Screenshot 2026-03-05 at 22 31 03" src="https://github.com/user-attachments/assets/58d90c68-f68d-49b8-9cb9-d10be152a071"; /> ### Modifications Create a SimpleCache object for each `pulsar-transaction-snapshot-recover` thread, and then lock contention will not occur. - The initialisation of Transaction Buffer Recovery for different namespaces will be assigned to fixed threads based on hashcode, which eliminates the problem of multi-threading competition - SimpleCache is a utility class. We did not remove the 'synchronized' keyword, but as long as the same object is used by only one thread, this mechanism will not have any performance impact ### 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 --> ### Matching PR in forked repository PR in forked repository: x -- 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]
