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https://issues.apache.org/jira/browse/OAK-4274?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15256034#comment-15256034
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Michael Dürig commented on OAK-4274:
------------------------------------
Relaying [~frm]'s [comment |
https://issues.apache.org/jira/browse/OAK-4211?focusedCommentId=15253795&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15253795]
from OAK-4211:
"The current implementation of {{FileAccess.Mapped}} might have another problem
regarding the way memory mapped files are unmapped. Every time a read operation
is performed on {{FileAccess.Mapped}}, we create a slice of the
{{MappedByteBuffer}} that references the original buffer. This means that we
(indirectly) expose a reference to the {{MappedByteBuffer}} to client code,
with the potential of impacting the unmapping of the memory mapped files that
we open."
> Memory-mapped files can't be explicitly unmapped
> ------------------------------------------------
>
> Key: OAK-4274
> URL: https://issues.apache.org/jira/browse/OAK-4274
> Project: Jackrabbit Oak
> Issue Type: Bug
> Components: segment-next, segmentmk
> Reporter: Francesco Mari
> Labels: gc, resilience
> Fix For: 1.6
>
>
> As described by [this JDK
> bug|http://bugs.java.com/view_bug.do?bug_id=4724038], there is no way to
> explicitly unmap memory mapped files. A memory mapped file is unmapped only
> if the corresponding {{MappedByteBuffer}} is garbage collected by the JVM.
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