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https://issues.apache.org/jira/browse/LUCENE-2620?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12901960#action_12901960
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Robert Muir commented on LUCENE-2620:
-------------------------------------
Hello Nick, thanks for your patch.
In trunk this is no problem, because wildcard query works in a very different
way and both foo**********bar and foo*bar are compiled to the same matcher:
{noformat}
WildcardQuery wq = new WildcardQuery(new Term("foo", "foo*******bar"));
WildcardQuery wq2 = new WildcardQuery(new Term("foo", "foo*bar"));
assertEquals(wq.automaton.getNumberOfStates(),
wq2.automaton.getNumberOfStates());
assertEquals(wq.automaton.getNumberOfTransitions(),
wq2.automaton.getNumberOfTransitions());
{noformat}
But at a glance, your patch looks like a potentially useful optimization for 3.x
> Queries with too many asterisks causing 100% CPU usage
> ------------------------------------------------------
>
> Key: LUCENE-2620
> URL: https://issues.apache.org/jira/browse/LUCENE-2620
> Project: Lucene - Java
> Issue Type: Bug
> Components: Search
> Affects Versions: 3.0.1
> Environment: Debian Lenny with Tomcat 5.5 and Mac OS X 10.6 with
> Tomcat 6, probably others
> Reporter: Nick Barkas
> Attachments: lucene-asterisks.diff
>
>
> If a search query has many adjacent asterisks (e.g. fo**************obar), I
> can get my webapp caught in a loop that does not seem to end in a reasonable
> amount of time and may in fact be infinite. For just a few asterisks the
> query eventually does return some results, but as I add more it takes a
> longer and longer amount of time. After about six or seven asterisks the
> query never seems to finish. Even if I abort the search, the thread handling
> the troublesome query continues running in the background and pinning a CPU.
> I found the problem in
> src/java/org/apache/lucene/search/WildcardTermEnum.java on Lucene 3.0.1 and
> it looks like 3.0.2 ought to be affected as well. I'm not sure about trunk,
> though. I have a patch that fixes the problem for me in 3.0.1.
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