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https://issues.apache.org/jira/browse/JENA-568?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stephen Allen resolved JENA-568.
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Resolution: Invalid
> Improve Fuseki/TDB transaction memory usage
> -------------------------------------------
>
> Key: JENA-568
> URL: https://issues.apache.org/jira/browse/JENA-568
> Project: Apache Jena
> Issue Type: Improvement
> Components: TDB
> Reporter: Stephen Allen
> Assignee: Stephen Allen
>
> TDB has to buffer in memory all of the modified blocks for a transaction
> before committing it. This causes out of memory exceptions when attempting
> to add a large number of statements in a single transaction.
> An easy way to fix this would be to copy the write block contents into a
> memory mapped file instead of heap memory ^†^. We can provide three user
> specified options for controlling the location of the temporary blocks:
> # JVM heap (default, and what we currently use)
> # Direct memory (process heap, but not in the JVM)
> # Memory mapped temporary file
> See this [Jena thread| http://markmail.org/thread/ckeevvhl2luevixw] for some
> additional discussion.
> ^†^ _The harder way would involve writing the old blocks to the journal, then
> writing the new blocks directly to the indexes, with a tombstone pointing to
> the old block in the journal so that readers could still retrieve the old
> version. This however would seem to require a substantial refactor, as well
> as a change to the on-disk database format._
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