Place warning about today's released Java7 version on Lucene/Solr/Root
webpage's news and send mail to java-user
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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 corrumption (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's fault! At
least disable loop optimizations using the -XX:-UseLoopPredicate JVM options to
not risk index corrumptions.
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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