lhotari commented on PR #24623: URL: https://github.com/apache/pulsar/pull/24623#issuecomment-3197678353
The recently added "experimental" test case `BrokerEntryCacheMultiBrokerTest.testTailingReadsRollingRestart` shows the real value of PIP-430 changes. It demonstrates a rolling restart where a producer is producing to a topic and there are 10 connected consumers with unique subscriptions. During the 30 second test period the producer produces as fast as it can and the consumers consume as fast as they can. There are 2 brokers in the cluster and a broker is restarted 3 times during the test period. The with PIP-430 defaults: ``` 2025-08-18T19:39:44,894 - INFO - [main:BrokerEntryCacheMultiBrokerTest] - Produced 21655 and Consumed 206425 messages (across 10 consumers with unique subscriptions) in total. Number of BK reads 74 with 2972 entries. Cache hits 98.56%, Cache misses 1.44%, Number of restarts 3 ``` with `cacheEvictionByExpectedReadCount=false` ``` 2025-08-18T19:41:17,119 - INFO - [main:BrokerEntryCacheMultiBrokerTest] - Produced 20767 and Consumed 197466 messages (across 10 consumers with unique subscriptions) in total. Number of BK reads 848 with 36220 entries. Cache hits 81.66%, Cache misses 18.34%, Number of restarts 3 ``` with `cacheEvictionByExpectedReadCount=false` and `managedLedgerCacheEvictionExtendTTLOfRecentlyAccessed=false` ``` 2025-08-18T19:42:34,214 - INFO - [main:BrokerEntryCacheMultiBrokerTest] - Produced 20888 and Consumed 198727 messages (across 10 consumers with unique subscriptions) in total. Number of BK reads 1309 with 53708 entries. Cache hits 72.97%, Cache misses 27.03%, Number of restarts 3 ``` The results vary quite a lot and these are values from single runs. However, it demonstrates a significant improvement in reducing the amount of cache misses in rolling restarts when PIP-430 defaults are used. -- 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]
