Jun Rao wrote:
I am wondering if anyone has experienced this problem. Sometimes when I
ran a job, a few map tasks (often just one) hang in the initializing phase
for more than 3 minutes (it normally finishes in a couple seconds). They
will eventually finish, but the whole job is slowed down considerably. The
weird thing is that the slow task is not deterministic. It doesn't always
occur and if does, can occur on any split and on any host.
I have not seen this.
Perhaps you can get a stack trace from the tasktracker while this is
happening?
Owen described how to get such stack traces in:
http://mail-archives.apache.org/mod_mbox/lucene-hadoop-user/200706.mbox/[EMAIL
PROTECTED]
Owen wrote:
One side note is that all of the servers have a servlet such that if
you do http://<node>:<port>/stacks you'll get a stack trace of all
the threads in the server. I find that useful for remote debugging.
*smile* Although if it is a task jvm that has the problem, then there
isn't a server for them.
(This should probably be added to the documentation or the wiki...)
Doug
