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https://issues.apache.org/jira/browse/HBASE-9644?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13776235#comment-13776235
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Victor Xu commented on HBASE-9644:
----------------------------------
HBase does have a fall back mechanism to double check the hfileblock's
checksum. However, in this case, it passed the first hbase checksum and then
skipped the second hdfs checksum. As a result, exception was thrown in the
decompress logic.
So my temporary solution to this problem is to add try-catch code to deal with
the exception, and return null if it happened, in order to trigger the hdfs
checksum mechanism.
It may take too much time to find the real cause of this problem in hbase
checksum mechanism.
> Regionserver throws java.lang.NoClassDefFoundError: Ljava/lang/InternalError
> exception while decompressing hfileblock
> ---------------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-9644
> URL: https://issues.apache.org/jira/browse/HBASE-9644
> Project: HBase
> Issue Type: Bug
> Components: HFile, regionserver
> Affects Versions: 0.94.10
> Environment: Linux 2.6.32-el5.x86_64
> Reporter: Victor Xu
>
> Regionserver threw a "java.lang.NoClassDefFoundError:
> Ljava/lang/InternalError" Exception when it decompressed a hfileblock.
> The exception detail is:
> 2013-09-15 05:44:03,612 ERROR
> org.apache.hadoop.hbase.regionserver.HRegionServer:
> java.lang.NoClassDefFoundError: Ljava/lang/InternalError
> at
> org.apache.hadoop.io.compress.snappy.SnappyDecompressor.decompressBytesDirect(Native
> Method)
> at
> org.apache.hadoop.io.compress.snappy.SnappyDecompressor.decompress(SnappyDecompressor.java:238)
> at
> org.apache.hadoop.io.compress.BlockDecompressorStream.decompress(BlockDecompressorStream.java:87)
> at
> org.apache.hadoop.io.compress.DecompressorStream.read(DecompressorStream.java:83)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:256)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> at org.apache.hadoop.io.IOUtils.readFully(IOUtils.java:192)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$AbstractFSReader.decompress(HFileBlock.java:1461)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderV2.readBlockDataInternal(HFileBlock.java:1890)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderV2.readBlockData(HFileBlock.java:1703)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2.readBlock(HFileReaderV2.java:342)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlockIndex$BlockIndexReader.loadDataBlockWithScanInfo(HFileBlockIndex.java:254)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.seekTo(HFileReaderV2.java:484)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.seekTo(HFileReaderV2.java:505)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.seekAtOrAfter(StoreFileScanner.java:220)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.seek(StoreFileScanner.java:140)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.<init>(StoreScanner.java:131)
> at
> org.apache.hadoop.hbase.regionserver.Store.getScanner(Store.java:2208)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.<init>(HRegion.java:3807)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.instantiateRegionScanner(HRegion.java:1825)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:1817)
> at
> org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:1794)
> at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4828)
> at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4802)
> at
> org.apache.hadoop.hbase.regionserver.HRegionServer.get(HRegionServer.java:2196)
> at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> org.apache.hadoop.hbase.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:320)
> at
> org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1426)
> Caused by: java.lang.ClassNotFoundException: Ljava.lang.InternalError
> at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
> ... 30 more
> There are two problems here:
> 1. Why use the class name 'Ljava/lang/InternalError' instead of
> 'java/lang/InternalError' in Snappy library?
> This involves the code of snappy lib, maybe there is a bug in it.
> 2. When I tried to read the hfileblock using HDFS tools, it told me that the
> local hfileblock didn't pass the file checksum and read another replica from
> remote datanode. Then here is the question, why hbase checksum cannot find
> this problem while hdfs can?
> This is my hbase-site.xml configure for checksum:
> <property>
> <name>dfs.client.read.shortcircuit</name>
> <value>true</value>
> <description></description>
> </property>
> <property>
> <name>dfs.client.read.shortcircuit.skip.checksum</name>
> <value>true</value>
> <description></description>
> </property>
> <property>
> <name>hbase.regionserver.checksum.verify</name>
> <value>true</value>
> <description></description>
> </property>
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