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From "Steven Rowe (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-3349) Place warning about today's released Java7 version on Lucene/Solr/Root webpage's news and send mail to java-user
Date Thu, 28 Jul 2011 18:05:11 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-3349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13072452#comment-13072452
] 

Steven Rowe commented on LUCENE-3349:
-------------------------------------

bq. In the case you upgrade to Java 7, remember that you have to reindex everything, as the
unicode version shipped with Java 7 changed and tokenization behaves differently!

StandardTokenizer is not dependent on JVM Unicode version, so this statement is neither true
in the strict sense nor in the "average" sense, assuming the "average" user employs StandardTokenizer/Analyzer.



> Place warning about today's released Java7 version on Lucene/Solr/Root webpage's news
and send mail to java-user
> ----------------------------------------------------------------------------------------------------------------
>
>                 Key: LUCENE-3349
>                 URL: https://issues.apache.org/jira/browse/LUCENE-3349
>             Project: Lucene - Java
>          Issue Type: Sub-task
>          Components: general/website
>         Environment: Java7
>            Reporter: Uwe Schindler
>            Assignee: Uwe Schindler
>
> Today, JDK/JRE 1.7.0 GA was released by Oracle. Unfortunately they didn't fix the Hotspot
problems affecting loops to be miscompiled (LUCENE-3335, LUCENE-3346). This can lead to Solr
crashing with default configuration on startup or sudden index corrumption depending on configuration.
> We should send an email to the java-user and solr-user list describing the problem. Also
place a note in the news section of Solr, Lucene Core and top-level website.
> I propose the following text:
> {quote}
> *Jul 28th, 2011: WARNING*
> Oracle released *Java 7* today. Unfortunately it contains some hotspot compiler optimizations,
which miscompile some loops in Lucene's code (this affects all versions released until today,
see Hotspot bug [http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7070134]). 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).
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).
> 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 [http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2011-July/005971.html]).
This means you cannot use 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 options to not risk index corruptions.
> Please note: Also Java 6 users are affected, if you 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 the case you upgrade to Java 7, remember that you have to reindex everything, as the
unicode version shipped with Java 7 changed and tokenization behaves differently!
> {quote}

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