[
https://issues.apache.org/jira/browse/LUCENE-9791?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17300410#comment-17300410
]
ASF subversion and git services commented on LUCENE-9791:
---------------------------------------------------------
Commit f171417e99548b9f5aa84605809ee58228e1e91a in lucene-solr's branch
refs/heads/branch_8x from pawel-bugalski-dynatrace
[ https://gitbox.apache.org/repos/asf?p=lucene-solr.git;h=f171417 ]
LUCENE-9791 Allow calling BytesRefHash#find concurrently (#8)
Removes `scratch1` field in `BytesRefHash` by accessing underlying bytes pool
directly
in `equals` method. As a result it is now possible to call `BytesRefHash#find`
concurrently as long as there are no concurrent modifications to BytesRefHash
instance
and it is correctly published.
This addresses the concurrency issue with Monitor (aka Luwak) since it
is using `BytesRefHash#find` concurrently without additional synchronization.
> Monitor (aka Luwak) has concurrency issues related to BytesRefHash#find
> -----------------------------------------------------------------------
>
> Key: LUCENE-9791
> URL: https://issues.apache.org/jira/browse/LUCENE-9791
> Project: Lucene - Core
> Issue Type: Bug
> Components: core/other
> Affects Versions: main (9.0), 8.7, 8.8
> Reporter: Paweł Bugalski
> Priority: Major
> Attachments: LUCENE-9791.patch, LUCENE-97910-8.x-backport.patch,
> LUCENE-9791_example.patch
>
> Time Spent: 4h 20m
> Remaining Estimate: 0h
>
> _org.apache.lucene.monitor.Monitor_ can sometimes *NOT* match a document that
> should be matched by one of registered queries if match operations are run
> concurrently from multiple threads.
> This is because sometimes in a concurrent environment
> _TermFilteredPresearcher_ might not select a query that could later on match
> one of documents being matched.
> Internally _TermFilteredPresearcher_ is using a term acceptor: an instance of
> _org.apache.lucene.monitor.QueryIndex.QueryTermFilter_. _QueryTermFilter_ is
> correctly initialized under lock and its internal state (a map of
> _org.apache.lucene.util.BytesRefHash_ instances) is correctly published.
> Later one when those instances are used concurrently a problem with
> _org.apache.lucene.util.BytesRefHash#find_ is triggered since it is not
> thread safe.
> _org.apache.lucene.util.BytesRefHash#find_ internally is using a private
> _org.apache.lucene.util.BytesRefHash#equals_ method, which is using an
> instance field _scratch1_ as a temporary buffer to compare its _ByteRef_
> parameter with contents of _ByteBlockPool_. This is not thread safe and can
> cause incorrect answers as well as _ArrayOutOfBoundException_.
> __
>
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org
For additional commands, e-mail: issues-h...@lucene.apache.org
