[jira] [Created] (KAFKA-12576) Renaming log segment should not result in a copy

["Jose Armando Garcia Sancio (Jira)" <ji...@apache.org>]

Jose Armando Garcia Sancio created KAFKA-12576:
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             Summary: Renaming log segment should not result in a copy
                 Key: KAFKA-12576
                 URL: https://issues.apache.org/jira/browse/KAFKA-12576
             Project: Kafka
          Issue Type: Bug
          Components: log, log cleaner
            Reporter: Jose Armando Garcia Sancio
            Assignee: Jose Armando Garcia Sancio


{{FileRecords::renameTo}} uses {{Utils::atomicMoveWithFallback}} to rename the backing File. The implementation for {{Utils::atomicMoveWithFallback}} will perform a non-atomic move if the atomic move fails. This can result in the content of the file being copied.

{{Log}} uses {{FileRecords::renameTo}} indirectly through {{LogSegment::changeFileSuffixes}} while holding the {{Log}} lock to delete segment and to replace clean segments.

This can cause the Kafka process to perform an expensive copy operation while holding a highly contended lock.

Given how {{Utils::atomicMoveWithFallback}} works there is also an issue where {{File file}} and {{FileChannel channel}} point to different file. Meaning writes to {{channel}} are not reflected in the file represented by {{file}}.

{{FileRecors::renameTo}} should be change to use only an atomic move and to fail if it cannot.



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