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From Sanne Grinovero <sanne.grinov...@gmail.com>
Subject Re: [WARNING] Index corruption and crashes in Apache Lucene Core / Apache Solr with Java 7
Date Fri, 29 Jul 2011 09:11:03 GMT
Hello,
thanks for the warning, that's a pretty nasty bug.

A patch was made for OpenJDK, if anybody is interested to try it out
that would be great:
http://hg.openjdk.java.net/hsx/hotspot-comp/hotspot/rev/4e761e7e6e12

Regards,
Sanne

2011/7/28 Uwe Schindler <uschindler@apache.org>:
> Hello Apache Lucene & Apache Solr users,
> Hello users of other Java-based Apache projects,
>
> Oracle released Java 7 today. Unfortunately it contains hotspot compiler
> optimizations, which miscompile some loops. This can affect code of several
> Apache projects. Sometimes JVMs only crash, but in several cases, results
> calculated can be incorrect, leading to bugs in applications (see Hotspot
> bugs 7070134 [1], 7044738 [2], 7068051 [3]).
>
> Apache Lucene Core and Apache Solr are two Apache projects, which are
> affected by these bugs, namely all versions released until today. Solr users
> with the default configuration will have Java crashing with SIGSEGV as soon
> as they start to index documents, as one affected part is the well-known
> Porter stemmer (see LUCENE-3335 [4]). Other loops in Lucene may be
> miscompiled, too, leading to index corruption (especially on Lucene trunk
> with pulsing codec; other loops may be affected, too - LUCENE-3346 [5]).
>
> These problems were detected only 5 days before the official Java 7 release,
> so Oracle had no time to fix those bugs, affecting also many more
> applications. In response to our questions, they proposed to include the
> fixes into service release u2 (eventually into service release u1, see [6]).
> This means you cannot use Apache Lucene/Solr with Java 7 releases before
> Update 2! If you do, please don't open bug reports, it is not the
> committers' fault! At least disable loop optimizations using the
> -XX:-UseLoopPredicate JVM option to not risk index corruptions.
>
> Please note: Also Java 6 users are affected, if they use one of those JVM
> options, which are not enabled by default: -XX:+OptimizeStringConcat or
> -XX:+AggressiveOpts
>
> It is strongly recommended not to use any hotspot optimization switches in
> any Java version without extensive testing!
>
> In case you upgrade to Java 7, remember that you may have to reindex, as the
> unicode version shipped with Java 7 changed and tokenization behaves
> differently (e.g. lowercasing). For more information, read
> JRE_VERSION_MIGRATION.txt in your distribution package!
>
> On behalf of the Lucene project,
> Uwe
>
> [1] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7070134
> [2] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7044738
> [3] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7068051
> [4] https://issues.apache.org/jira/browse/LUCENE-3335
> [5] https://issues.apache.org/jira/browse/LUCENE-3346
> [6] http://s.apache.org/StQ
>
> -----
> Uwe Schindler
> uschindler@apache.org
> Apache Lucene PMC Member / Committer
> Bremen, Germany
> http://lucene.apache.org/
>
>
>
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