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https://issues.apache.org/jira/browse/JENA-624?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15041305#comment-15041305
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Andy Seaborne commented on JENA-624:
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We will also need to evaluate whether the code needs to {{.remove}}
TheradLocals as it clears up a transaction. It is a trade off of removing vs
reusing for the same thread. This why I am seeking to minimize their use.
Elsewhere
[TransactionalComponentLifecycle#L136|https://github.com/afs/mantis/blob/master/dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentLifecycle.java#L136]
==>
[TransactionalComponentLifecycle#L220|https://github.com/afs/mantis/blob/master/dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentLifecycle.java#L220]
The comment in the last one is experience that ThreadLocals cause objects to be
held for much longer than expected and I was seeing total memory grow in
transaction cycles even without threads being created/destroyed. A system that
creates a thread, have it execute and then die, is worse again as the thread
local and anything it can reference is still live.
> Develop a new in-memory RDF Dataset implementation
> --------------------------------------------------
>
> Key: JENA-624
> URL: https://issues.apache.org/jira/browse/JENA-624
> Project: Apache Jena
> Issue Type: Improvement
> Reporter: Andy Seaborne
> Assignee: A. Soroka
> Labels: java, linked_data, rdf
>
> The current (Jan 2014) Jena in-memory dataset uses a general purpose
> container that works for any storage technology for graphs together with
> in-memory graphs.
> This project would develop a new implementation design specifically for RDF
> datasets (triples and quads) and efficient SPARQL execution, for example,
> using multi-core parallel operations and/or multi-version concurrent
> datastructures to maximise true parallel operation.
> This is a system project suitable for someone interested in datatbase
> implementation, datastructure design and implementation, operating systems or
> distributed systems.
> Note that TDB can operate in-memory using a simulated disk with
> copy-in/copy-out semantics for disk-level operations. It is for faithful
> testing TDB infrastructure and is not designed performance, general in-memory
> use or use at scale. While lesson may be learnt from that system, TDB
> in-memory is not the answer here.
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