That is odd---- why would it crash when your m/r job did not rely on snappy?
One possibility : Maybe because your input is snappy compressed, Hadoop is detecting that compression, and trying to use the snappy codec to decompress.? Jay Vyas MMSB UCHC On Apr 15, 2012, at 5:08 AM, Bas Hickendorff <hickendorff...@gmail.com> wrote: > Hello John, > > I did restart them (in fact, I did a full reboot of the machine). The > error is still there. > > I guess my question is: is it expected that Hadoop needs to do > something with the Snappycodec when mapred.compress.map.output is set > to false? > > Regards, > > Bas > > On Sun, Apr 15, 2012 at 12:04 PM, john smith <js1987.sm...@gmail.com> wrote: >> Can you restart tasktrackers once and run the job again? It refreshes the >> class path. >> >> On Sun, Apr 15, 2012 at 11:58 AM, Bas Hickendorff >> <hickendorff...@gmail.com>wrote: >> >>> Thanks. >>> >>> The native snappy libraries I have installed. However, I use the >>> normal jars that you get when downloading Hadoop, I am not compiling >>> Hadoop myself. >>> >>> I do not want to use the snappy codec (I don't care about compression >>> at the moment), but it seems it is needed anyway? I added this to the >>> mapred-site.xml: >>> >>> <property> >>> <name>mapred.compress.map.output</name> >>> <value>false</value> >>> </property> >>> >>> But it still fails with the error of my previous email (SnappyCodec not >>> found). >>> >>> Regards, >>> >>> Bas >>> >>> >>> On Sat, Apr 14, 2012 at 6:30 PM, Vinod Kumar Vavilapalli >>> <vino...@hortonworks.com> wrote: >>>> >>>> Hadoop has integrated snappy via installed native libraries instead of >>> snappy-java.jar (ref https://issues.apache.org/jira/browse/HADOOP-7206) >>>> - You need to have the snappy system libraries (snappy and >>> snappy-devel) installed before you compile hadoop. (RPMs are available on >>> the web, http://pkgs.org/centos-5-rhel-5/epel-i386/21/ for example) >>>> - When you build hadoop, you will need to compile the native >>> libraries(by passing -Dcompile.native=true to ant) to avail snappy support. >>>> - You also need to make sure that snappy system library is available on >>> the library path for all mapreduce tasks at runtime. Usually if you install >>> them on /usr/lib or /usr/local/lib, it should work. >>>> >>>> HTH, >>>> +Vinod >>>> >>>> On Apr 14, 2012, at 4:36 AM, Bas Hickendorff wrote: >>>> >>>>> Hello, >>>>> >>>>> When I start a map-reduce job, it starts, and after a short while, >>>>> fails with the error below (SnappyCodec not found). >>>>> >>>>> I am currently starting the job from other Java code (so the Hadoop >>>>> executable in the bin directory is not used anymore), but in principle >>>>> this seems to work (in the admin of the Jobtracker the job shows up >>>>> when it starts). However after a short while the map task fails with: >>>>> >>>>> >>>>> java.lang.IllegalArgumentException: Compression codec >>>>> org.apache.hadoop.io.compress.SnappyCodec not found. >>>>> at >>> org.apache.hadoop.io.compress.CompressionCodecFactory.getCodecClasses(CompressionCodecFactory.java:96) >>>>> at >>> org.apache.hadoop.io.compress.CompressionCodecFactory.<init>(CompressionCodecFactory.java:134) >>>>> at >>> org.apache.hadoop.mapreduce.lib.input.LineRecordReader.initialize(LineRecordReader.java:62) >>>>> at >>> org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.initialize(MapTask.java:522) >>>>> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:763) >>>>> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370) >>>>> at org.apache.hadoop.mapred.Child$4.run(Child.java:255) >>>>> at java.security.AccessController.doPrivileged(Native Method) >>>>> at javax.security.auth.Subject.doAs(Subject.java:416) >>>>> at >>> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093) >>>>> at org.apache.hadoop.mapred.Child.main(Child.java:249) >>>>> Caused by: java.lang.ClassNotFoundException: >>>>> org.apache.hadoop.io.compress.SnappyCodec >>>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:217) >>>>> at java.security.AccessController.doPrivileged(Native Method) >>>>> at java.net.URLClassLoader.findClass(URLClassLoader.java:205) >>>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:321) >>>>> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) >>>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:266) >>>>> at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:334) >>>>> at java.lang.Class.forName0(Native Method) >>>>> at java.lang.Class.forName(Class.java:264) >>>>> at >>> org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:820) >>>>> at >>> org.apache.hadoop.io.compress.CompressionCodecFactory.getCodecClasses(CompressionCodecFactory.java:89) >>>>> ... 10 more >>>>> >>>>> >>>>> I confirmed that the SnappyCodec class is present in the >>>>> hadoop-core-1.0.2.jar, and the snappy-java-1.0.4.1.jar is present as >>>>> well. The directory of those jars is on the HADOOP_CLASSPATH, but it >>>>> seems it still cannot find it. I also checked that the config files of >>>>> Hadoop are read. I run all nodes on localhost. >>>>> >>>>> Any suggestions on what could be the cause of the issue? >>>>> >>>>> Regards, >>>>> >>>>> Bas >>>> >>>
