System Administration - eXist: A NoSQL Database and Application Development Platform - page 414

64-bit. Specify the vendor, version, and CPU architecture of the Java JRE or JDK
that you are using as well. The Java version can be obtained by running the com‐
mand java -version , and vendor information by examining the java.vm prop‐
erties when running java -XshowSettings:properties -version .
• Be sure to report how much memory is available to the operating system, includ‐
ing how much is allocated to eXist (i.e., the -Xmx setting), and how much is allo‐
cated to the general cache and to the collections cache in $EXIST_HOME/
conf.xml .
• When reporting errors or bugs with eXist, make sure to include any pertinent
WARN- or ERROR-level log messages from the logfiles, in particular
$EXIST_HOME/webapp/WEB-INF/logs/exist.log .
• If you believe that eXist has frozen in some way (deadlock/livelock) and is not
correctly responding to incoming requests, then a thread dump of the eXist pro‐
cess can be invaluable to the developers. You can obtain a thread dump through
one of several methods, such as:
— Using the jstack tool that comes with your JRE . For example, by running
jstack -l 51617 > exist-jstack.txt , where 51617 is the process ID (PID)
of eXist, you can get a file exist-jstack.txt containing a thread dump. You can
find out the PID of eXist by running the command jps .
— By sending the QUIT signal using the kill command on Unix/Linux/Mac
systems. For example, by running kill -s QUIT 19241 > exist-dump.txt ,
where 19241 is the PID of eXist, you can get a file exist-dump.txt containing a
thread dump.
• If the JVM running eXist has crashed, then a file whose name starts with
hs_err_pid will be created. You should keep a copy in case it's requested by the
eXist developers when you're reporting a problem. Ultimately, you may be asked
to send a copy to the JRE/JDK vendor if the file reveals a bug in the JVM.
• Remember, when reporting bugs, you need to be able to explain how to repro‐
duce the issue to the community. If a developer cannot reproduce your issue
easily, then it becomes hard or impossible for her to assist you. This is particu‐
larly important when reporting problems with your XQuery scripts. You should
be concerned with creating an absolutely minimal example XQuery script that
isolates and reproduces the problem you are experiencing. The easier you can
make it for a developer to reproduce your issue, the more likely you will be to get
a quick fix. Simply sending several thousand lines of XQuery code and saying
that there is a problem somewhere will most likely not result in a solution to your
problem anytime soon!