You need three things. 1 install snappy to a place the system can pick it out automatically or add it to your java.library.path
Then add the full name of the codec to io.compression.codecs. hive> set io.compression.codecs; io.compression.codecs=org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.BZip2Codec,org.apache.hadoop.io.compress.SnappyCodec Edward On Sun, Apr 15, 2012 at 8:36 AM, Bas Hickendorff <hickendorff...@gmail.com> wrote: > Hello Jay, > > My input is just a csv file (created it myself), so I am sure it is > not compressed in any way. Also, the same input works when I use the > standalone example (using the hadoop executable in the bin folder). > When I try to integrate it in a larger java program it fails.... :( > > Regards, > > Bas > > On Sun, Apr 15, 2012 at 2:30 PM, JAX <jayunit...@gmail.com> wrote: >> 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 >>>>>> >>>>>
