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Divij Vaidya commented on KAFKA-15609: -------------------------------------- Thank you for clarifying [~ocadaruma] and thank you for the quick tests. We actually want to test the condition where we write to a MMap but read using (non direct) File I/O. We want to validate that even if MMap may not have been flushed, the data read via File I/O is consistent. Would you have time to quickly test that? > Also, in my understanding, page cache is directly mapped to the mmap area so > even when we try to read the file with ordinary read() call which is written > by mmap, the content should be consistent. This is the point about which I am not able to find any concrete implementation. Would you happen to have some reference that I can read about this? > Corrupted index uploaded to remote tier > --------------------------------------- > > Key: KAFKA-15609 > URL: https://issues.apache.org/jira/browse/KAFKA-15609 > Project: Kafka > Issue Type: Bug > Components: Tiered-Storage > Affects Versions: 3.6.0 > Reporter: Divij Vaidya > Priority: Minor > > While testing Tiered Storage, we have observed corrupt indexes being present > in remote tier. One such situation is covered here at > https://issues.apache.org/jira/browse/KAFKA-15401. This Jira presents another > such possible case of corruption. > Potential cause of index corruption: > We want to ensure that the file we are passing to RSM plugin contains all the > data which is present in MemoryByteBuffer i.e. we should have flushed the > MemoryByteBuffer to the file using force(). In Kafka, when we close a > segment, indexes are flushed asynchronously [1]. Hence, it might be possible > that when we are passing the file to RSM, the file doesn't contain flushed > data. Hence, we may end up uploading indexes which haven't been flushed yet. > Ideally, the contract should enforce that we force flush the content of > MemoryByteBuffer before we give the file for RSM. This will ensure that > indexes are not corrupted/incomplete. > [1] > [https://github.com/apache/kafka/blob/4150595b0a2e0f45f2827cebc60bcb6f6558745d/core/src/main/scala/kafka/log/UnifiedLog.scala#L1613] > -- This message was sent by Atlassian Jira (v8.20.10#820010)