Fix SharedBytes mmap leak by closing parent arena on close#142460
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ChrisHegarty merged 4 commits intoelastic:mainfrom Feb 13, 2026
Merged
Fix SharedBytes mmap leak by closing parent arena on close#142460ChrisHegarty merged 4 commits intoelastic:mainfrom
ChrisHegarty merged 4 commits intoelastic:mainfrom
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ChrisHegarty
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Pinging @elastic/es-distributed (Team:Distributed) |
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Hi @ChrisHegarty, I've created a changelog YAML for you. |
fcofdez
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Feb 13, 2026
x-pack/plugin/blob-cache/src/test/java/org/elasticsearch/blobcache/shared/SharedBytesTests.java
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…42460) SharedBytes memory-maps its cache file using Arena.ofShared(), which requires explicit closing to release the mapping. The parent CloseableMappedByteBuffer objects (which own the arenas) were stored in a local variable in the constructor and never closed - only slices (with arena = null) were retained in the IO objects. As a result, mapped memory was never released until JVM exit, leaking the cache file's disk blocks even after the file was deleted. This is observable in tests that repeatedly create and tear down searchable snapshot infrastructure (e.g. VectorScorerOSQBenchmarkTests), where each iteration leaked a 16+ MB cache file. The fix retains the parent mmap buffers as a field and closes them in closeInternal() via IOUtils.close before closing the file channel.
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SharedBytes memory-maps its cache file using
Arena.ofShared(), which requires explicit closing to release the mapping. The parentCloseableMappedByteBufferobjects (which own the arenas) were stored in a local variable in the constructor and never closed - only slices (witharena = null) were retained in theIOobjects. As a result, mapped memory was never released until JVM exit, leaking the cache file's disk blocks even after the file was deleted.This is observable in tests that repeatedly create and tear down searchable snapshot infrastructure (e.g.
VectorScorerOSQBenchmarkTests), where each iteration leaked a 16+ MB cache file. The fix retains the parent mmap buffers as a field and closes them incloseInternal()viaIOUtils.closebefore closing the file channel.This issue was caused by the changes in #140371