Chris Hostetter wrote:
: I'm a new user of solr but I have worked a bit with Lucene before. I get
: some out of memory exception when optimizing the index through Solr and
: I would like to find out why. However, the only message I get on
: standard output is: Jul 30, 2009 9:20:22 PM
: org.apache.solr.common.SolrException log SEVERE:
: java.lang.OutOfMemoryError: Java heap space
:
: Is there a way to get a stack trace for this exception? I had a look
: into the java.util.logging options and didn't find anything.
FWIW #1: OutOfMemoryError is a java "Error" not an "Exception" ...
Exceptions and Errors are both Throwable, but an Error is not an
Exception. this is a really importatn distinction (see below)
FWIW #2: when dealing with an OOM, a stack trace is almost never useful.
as mentioned in other threads, a heapdump is the most useful diagnostic
tool
FWIW #3: the formatting of Throwables in log files is 100% dependent
on the configuration of the log manager -- the client code doing
the logging just specifies the Throwable object -- it's up to the
Formatter to decide how to output it.
Ok .. on to the meat of hte issue...
OOM Errors are a particularly devious class of errors: they don't
neccessarily have stack traces (depending on your VM impl, and the state
of the VM when it tries to log the OOM) ....
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4753347
http://blogs.sun.com/alanb/entry/outofmemoryerror_looks_a_bit_better
...on any *Exception* you should get a detailed stacktrace in the logs
(unless you have a really screwed up LogManger configs), but when dealing
with *Errors* like OutOfMemoryError, all bets are off as to what hte VM
can give you.
I had some success in debugging this type of problems when I would
generate a heap dump on OOM (it's a JVM flag) and then use a tool like
HAT to find largest objects and references to them.
--
Best regards,
Andrzej Bialecki <><
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