Hi Hemanth, Nice to see this. I didnot know about this till now.
But few one more issue.. the dump file did not get created.. The following are the logs ttempt_201302211510_81218_m_000000_0: /data/1/mapred/local/taskTracker/distcache/8776089957260881514_-363500746_715125253/cmp111wcd/user/ims-b/nagarjuna/AddressId_Extractor/Numbers attempt_201302211510_81218_m_000000_0: java.lang.OutOfMemoryError: Java heap space attempt_201302211510_81218_m_000000_0: Dumping heap to ./heapdump.hprof ... attempt_201302211510_81218_m_000000_0: Heap dump file created [210641441 bytes in 3.778 secs] attempt_201302211510_81218_m_000000_0: # attempt_201302211510_81218_m_000000_0: # java.lang.OutOfMemoryError: Java heap space attempt_201302211510_81218_m_000000_0: # -XX:OnOutOfMemoryError="./dump.sh" attempt_201302211510_81218_m_000000_0: # Executing /bin/sh -c "./dump.sh"... attempt_201302211510_81218_m_000000_0: put: File myheapdump.hprof does not exist. attempt_201302211510_81218_m_000000_0: log4j:WARN No appenders could be found for logger (org.apache.hadoop.hdfs.DFSClient). On Wed, Mar 27, 2013 at 2:29 PM, Hemanth Yamijala <yhema...@thoughtworks.com > wrote: > Couple of things to check: > > Does your class com.hadoop.publicationMrPOC.Launcher implement the Tool > interface ? You can look at an example at ( > http://hadoop.apache.org/docs/r1.0.4/mapred_tutorial.html#Source+Code-N110D0). > That's what accepts the -D params on command line. Alternatively, you can > also set the same in the configuration object like this, in your launcher > code: > > Configuration conf = new Configuration() > > conf.set("mapred.create.symlink", "yes"); > > conf.set("mapred.cache.files", > "hdfs:///user/hemanty/scripts/copy_dump.sh#copy_dump.sh"); > > conf.set("mapred.child.java.opts", > > "-Xmx200m -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=./heapdump.hprof > -XX:OnOutOfMemoryError=./copy_dump.sh"); > > > Second, the position of the arguments matters. I think the command should > be > > hadoop jar -Dmapred.create.symlink=yes > -Dmapred.cache.files=hdfs:///user/ims-b/dump.sh#dump.sh > -Dmapred.reduce.child.java.opts='-Xmx2048m -XX:+HeapDumpOnOutOfMemoryError > -XX:HeapDumpPath=./myheapdump.hprof -XX:OnOutOfMemoryError=./dump.sh' > com.hadoop.publicationMrPOC.Launcher Fudan\ Univ > > Thanks > Hemanth > > > On Wed, Mar 27, 2013 at 1:58 PM, nagarjuna kanamarlapudi < > nagarjuna.kanamarlap...@gmail.com> wrote: > >> Hi Hemanth/Koji, >> >> Seems the above script doesn't work for me. Can u look into the >> following and suggest what more can I do >> >> >> hadoop fs -cat /user/ims-b/dump.sh >> #!/bin/sh >> hadoop dfs -put myheapdump.hprof /tmp/myheapdump_ims/${PWD//\//_}.hprof >> >> >> hadoop jar LL.jar com.hadoop.publicationMrPOC.Launcher Fudan\ Univ >> -Dmapred.create.symlink=yes >> -Dmapred.cache.files=hdfs:///user/ims-b/dump.sh#dump.sh >> -Dmapred.reduce.child.java.opts='-Xmx2048m -XX:+HeapDumpOnOutOfMemoryError >> -XX:HeapDumpPath=./myheapdump.hprof -XX:OnOutOfMemoryError=./dump.sh' >> >> >> I am not able to see the heap dump at /tmp/myheapdump_ims >> >> >> >> Erorr in the mapper : >> >> Caused by: java.lang.reflect.InvocationTargetException >> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) >> at >> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) >> at >> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) >> at java.lang.reflect.Method.invoke(Method.java:597) >> at >> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88) >> ... 17 more >> Caused by: java.lang.OutOfMemoryError: Java heap space >> at java.util.Arrays.copyOf(Arrays.java:2734) >> at java.util.ArrayList.ensureCapacity(ArrayList.java:167) >> at java.util.ArrayList.add(ArrayList.java:351) >> at >> com.hadoop.publicationMrPOC.PublicationMapper.configure(PublicationMapper.java:59) >> ... 22 more >> >> >> >> >> >> On Wed, Mar 27, 2013 at 10:16 AM, Hemanth Yamijala < >> yhema...@thoughtworks.com> wrote: >> >>> Koji, >>> >>> Works beautifully. Thanks a lot. I learnt at least 3 different things >>> with your script today ! >>> >>> Hemanth >>> >>> >>> On Tue, Mar 26, 2013 at 9:41 PM, Koji Noguchi <knogu...@yahoo-inc.com>wrote: >>> >>>> Create a dump.sh on hdfs. >>>> >>>> $ hadoop dfs -cat /user/knoguchi/dump.sh >>>> #!/bin/sh >>>> hadoop dfs -put myheapdump.hprof >>>> /tmp/myheapdump_knoguchi/${PWD//\//_}.hprof >>>> >>>> Run your job with >>>> >>>> -Dmapred.create.symlink=yes >>>> -Dmapred.cache.files=hdfs:///user/knoguchi/dump.sh#dump.sh >>>> -Dmapred.reduce.child.java.opts='-Xmx2048m >>>> -XX:+HeapDumpOnOutOfMemoryError >>>> -XX:HeapDumpPath=./myheapdump.hprof -XX:OnOutOfMemoryError=./dump.sh' >>>> >>>> This should create the heap dump on hdfs at /tmp/myheapdump_knoguchi. >>>> >>>> Koji >>>> >>>> >>>> On Mar 26, 2013, at 11:53 AM, Hemanth Yamijala wrote: >>>> >>>> > Hi, >>>> > >>>> > I tried to use the -XX:+HeapDumpOnOutOfMemoryError. Unfortunately, >>>> like I suspected, the dump goes to the current work directory of the task >>>> attempt as it executes on the cluster. This directory is cleaned up once >>>> the task is done. There are options to keep failed task files or task files >>>> matching a pattern. However, these are NOT retaining the current working >>>> directory. Hence, there is no option to get this from a cluster AFAIK. >>>> > >>>> > You are effectively left with the jmap option on pseudo distributed >>>> cluster I think. >>>> > >>>> > Thanks >>>> > Hemanth >>>> > >>>> > >>>> > On Tue, Mar 26, 2013 at 11:37 AM, Hemanth Yamijala < >>>> yhema...@thoughtworks.com> wrote: >>>> > If your task is running out of memory, you could add the option >>>> -XX:+HeapDumpOnOutOfMemoryError >>>> > to mapred.child.java.opts (along with the heap memory). However, I am >>>> not sure where it stores the dump.. You might need to experiment a little >>>> on it.. Will try and send out the info if I get time to try out. >>>> > >>>> > >>>> > Thanks >>>> > Hemanth >>>> > >>>> > >>>> > On Tue, Mar 26, 2013 at 10:23 AM, nagarjuna kanamarlapudi < >>>> nagarjuna.kanamarlap...@gmail.com> wrote: >>>> > Hi hemanth, >>>> > >>>> > This sounds interesting, will out try out that on the pseudo cluster. >>>> But the real problem for me is, the cluster is being maintained by third >>>> party. I only have have a edge node through which I can submit the jobs. >>>> > >>>> > Is there any other way of getting the dump instead of physically >>>> going to that machine and checking out. >>>> > >>>> > >>>> > >>>> > On Tue, Mar 26, 2013 at 10:12 AM, Hemanth Yamijala < >>>> yhema...@thoughtworks.com> wrote: >>>> > Hi, >>>> > >>>> > One option to find what could be taking the memory is to use jmap on >>>> the running task. The steps I followed are: >>>> > >>>> > - I ran a sleep job (which comes in the examples jar of the >>>> distribution - effectively does nothing in the mapper / reducer). >>>> > - From the JobTracker UI looked at a map task attempt ID. >>>> > - Then on the machine where the map task is running, got the PID of >>>> the running task - ps -ef | grep <task attempt id> >>>> > - On the same machine executed jmap -histo <pid> >>>> > >>>> > This will give you an idea of the count of objects allocated and >>>> size. Jmap also has options to get a dump, that will contain more >>>> information, but this should help to get you started with debugging. >>>> > >>>> > For my sleep job task - I saw allocations worth roughly 130 MB. >>>> > >>>> > Thanks >>>> > hemanth >>>> > >>>> > >>>> > >>>> > >>>> > On Mon, Mar 25, 2013 at 6:43 PM, Nagarjuna Kanamarlapudi < >>>> nagarjuna.kanamarlap...@gmail.com> wrote: >>>> > I have a lookup file which I need in the mapper. So I am trying to >>>> read the whole file and load it into list in the mapper. >>>> > >>>> > >>>> > For each and every record Iook in this file which I got from >>>> distributed cache. >>>> > >>>> > — >>>> > Sent from iPhone >>>> > >>>> > >>>> > On Mon, Mar 25, 2013 at 6:39 PM, Hemanth Yamijala < >>>> yhema...@thoughtworks.com> wrote: >>>> > >>>> > Hmm. How are you loading the file into memory ? Is it some sort of >>>> memory mapping etc ? Are they being read as records ? Some details of the >>>> app will help >>>> > >>>> > >>>> > On Mon, Mar 25, 2013 at 2:14 PM, nagarjuna kanamarlapudi < >>>> nagarjuna.kanamarlap...@gmail.com> wrote: >>>> > Hi Hemanth, >>>> > >>>> > I tried out your suggestion loading 420 MB file into memory. It threw >>>> java heap space error. >>>> > >>>> > I am not sure where this 1.6 GB of configured heap went to ? >>>> > >>>> > >>>> > On Mon, Mar 25, 2013 at 12:01 PM, Hemanth Yamijala < >>>> yhema...@thoughtworks.com> wrote: >>>> > Hi, >>>> > >>>> > The free memory might be low, just because GC hasn't reclaimed what >>>> it can. Can you just try reading in the data you want to read and see if >>>> that works ? >>>> > >>>> > Thanks >>>> > Hemanth >>>> > >>>> > >>>> > On Mon, Mar 25, 2013 at 10:32 AM, nagarjuna kanamarlapudi < >>>> nagarjuna.kanamarlap...@gmail.com> wrote: >>>> > io.sort.mb = 256 MB >>>> > >>>> > >>>> > On Monday, March 25, 2013, Harsh J wrote: >>>> > The MapTask may consume some memory of its own as well. What is your >>>> > io.sort.mb (MR1) or mapreduce.task.io.sort.mb (MR2) set to? >>>> > >>>> > On Sun, Mar 24, 2013 at 3:40 PM, nagarjuna kanamarlapudi >>>> > <nagarjuna.kanamarlap...@gmail.com> wrote: >>>> > > Hi, >>>> > > >>>> > > I configured my child jvm heap to 2 GB. So, I thought I could >>>> really read >>>> > > 1.5GB of data and store it in memory (mapper/reducer). >>>> > > >>>> > > I wanted to confirm the same and wrote the following piece of code >>>> in the >>>> > > configure method of mapper. >>>> > > >>>> > > @Override >>>> > > >>>> > > public void configure(JobConf job) { >>>> > > >>>> > > System.out.println("FREE MEMORY -- " >>>> > > >>>> > > + Runtime.getRuntime().freeMemory()); >>>> > > >>>> > > System.out.println("MAX MEMORY ---" + >>>> Runtime.getRuntime().maxMemory()); >>>> > > >>>> > > } >>>> > > >>>> > > >>>> > > Surprisingly the output was >>>> > > >>>> > > >>>> > > FREE MEMORY -- 341854864 = 320 MB >>>> > > MAX MEMORY ---1908932608 = 1.9 GB >>>> > > >>>> > > >>>> > > I am just wondering what processes are taking up that extra 1.6GB >>>> of heap >>>> > > which I configured for the child jvm heap. >>>> > > >>>> > > >>>> > > Appreciate in helping me understand the scenario. >>>> > > >>>> > > >>>> > > >>>> > > Regards >>>> > > >>>> > > Nagarjuna K >>>> > > >>>> > > >>>> > > >>>> > >>>> > >>>> > >>>> > -- >>>> > Harsh J >>>> > >>>> > >>>> > -- >>>> > Sent from iPhone >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> >>>> >>> >> >
