[jira] [Commented] (JENA-848) jena-text Lucene concurrency issues

["ASF subversion and git services (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14276277#comment-14276277 ] 

ASF subversion and git services commented on JENA-848:
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Commit 4ee8d9e37885595710dc3a3f4d28d4aedc39f51a in jena's branch refs/heads/master from [~sallen]
[ https://git-wip-us.apache.org/repos/asf?p=jena.git;h=4ee8d9e ]

JENA-848 : Fix concurrency control for in-process Lucene index


> jena-text Lucene concurrency issues
> -----------------------------------
>
>                 Key: JENA-848
>                 URL: https://issues.apache.org/jira/browse/JENA-848
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: Text
>            Reporter: Stephen Allen
>            Assignee: Stephen Allen
>
> When using jena-text with an in-process Lucene index, there are concurrency issues when multiple requests are accessing the Dataset in using transactions.
> It appears the problem is that a new Lucene IndexWriter is created at every transaction start with no concurrency control.  Instead the solution should be to create a single IndexWriter when the DatasetGraphText is created and use that for all requests.  This works because the Lucene IndexWriter is thread safe and designed for concurrent access.
> This should also increase performance by not continually opening and closing the IndexWriter.  Also we can use Near Real-Time (NRT) IndexReaders that don't have to wait until changes are pushed to disk.
> If concurrent access is not controlled then you can end up with IndexWriter objects being closed while they are still in use by other threads:
> {code}
> org.apache.lucene.store.AlreadyClosedException: this IndexWriter is closed
>         at org.apache.lucene.index.IndexWriter.ensureOpen(IndexWriter.java:645)
>         at org.apache.lucene.index.IndexWriter.commitInternal(IndexWriter.java:2974)
>         at org.apache.lucene.index.IndexWriter.commit(IndexWriter.java:2954)
>         at org.apache.jena.query.text.TextIndexLucene.finishIndexing(TextIndexLucene.java:122)
>         at org.apache.jena.query.text.TextDocProducerTriples.finish(TextDocProducerTriples.java:46)
>         at org.apache.jena.query.text.DatasetGraphText.commit(DatasetGraphText.java:122)
>         at org.apache.jena.query.text.TestLuceneWithMultipleThreads$2.run(TestLuceneWithMultipleThreads.java:156)
>         at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
>         at java.util.concurrent.FutureTask.run(FutureTask.java:266)
>         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
>         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
>         at java.lang.Thread.run(Thread.java:744)
> {code}



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