Sorry about using attachment. The code is below for the reference.
(I will also file a jira as you suggesting)
package codectest;
import com.hadoop.compression.lzo.LzoCodec;
import java.io.IOException;
import java.util.Formatter;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.io.MapFile;
import org.apache.hadoop.io.SequenceFile.CompressionType;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.DefaultCodec;
import org.apache.hadoop.io.compress.SnappyCodec;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
public class MapFileCodecTest implements Tool {
private Configuration conf = new Configuration();
private void createMapFile(Configuration conf, FileSystem fs, String path,
CompressionCodec codec, CompressionType type, int records)
throws IOException {
MapFile.Writer writer = new MapFile.Writer(conf, fs, path,
Text.class, Text.class,
type, codec, null);
Text key = new Text();
for (int j = 0; j < records; j++) {
StringBuilder sb = new StringBuilder();
Formatter formatter = new Formatter(sb);
formatter.format("%03d", j);
key.set(sb.toString());
writer.append(key, key);
}
writer.close();
}
private void testCodec(Configuration conf, Class<? extends
CompressionCodec> clazz,
CompressionType type, int records) throws IOException {
FileSystem fs = FileSystem.getLocal(conf);
try {
System.out.println("Creating MapFiles with " + records +
" records using codec " + clazz.getSimpleName());
String path = clazz.getSimpleName() + records;
createMapFile(conf, fs, path, clazz.newInstance(), type, records);
MapFile.Reader reader = new MapFile.Reader(fs, path, conf);
Text key1 = new Text("002");
if (reader.get(key1, new Text()) != null) {
System.out.println("1st key found");
}
Text key2 = new Text("004");
if (reader.get(key2, new Text()) != null) {
System.out.println("2nd key found");
}
} catch (Throwable ex) {
ex.printStackTrace();
}
}
@Override
public int run(String[] strings) throws Exception {
System.out.println("Using native library " +
System.getProperty("java.library.path"));
testCodec(conf, DefaultCodec.class, CompressionType.RECORD, 100);
testCodec(conf, SnappyCodec.class, CompressionType.RECORD, 100);
testCodec(conf, LzoCodec.class, CompressionType.RECORD, 100);
testCodec(conf, DefaultCodec.class, CompressionType.RECORD, 10);
testCodec(conf, SnappyCodec.class, CompressionType.RECORD, 10);
testCodec(conf, LzoCodec.class, CompressionType.RECORD, 10);
testCodec(conf, DefaultCodec.class, CompressionType.BLOCK, 100);
testCodec(conf, SnappyCodec.class, CompressionType.BLOCK, 100);
testCodec(conf, LzoCodec.class, CompressionType.BLOCK, 100);
testCodec(conf, DefaultCodec.class, CompressionType.BLOCK, 10);
testCodec(conf, SnappyCodec.class, CompressionType.BLOCK, 10);
testCodec(conf, LzoCodec.class, CompressionType.BLOCK, 10);
return 0;
}
@Override
public void setConf(Configuration c) {
this.conf = c;
}
@Override
public Configuration getConf() {
return conf;
}
public static void main(String[] args) throws Exception {
ToolRunner.run(new MapFileCodecTest(), args);
}
}
On 5/21/12, Todd Lipcon <t...@cloudera.com> wrote:
> Hi Jason,
>
> Sounds like a bug. Unfortunately the mailing list strips attachments.
>
> Can you file a jira in the HADOOP project, and attach your test case there?
>
> Thanks
> Todd
>
> On Mon, May 21, 2012 at 3:57 PM, Jason B <urg...@gmail.com> wrote:
>> I am using Cloudera distribution cdh3u1.
>>
>> When trying to check native codecs for better decompression
>> performance such as Snappy or LZO, I ran into issues with random
>> access using MapFile.Reader.get(key, value) method.
>> First call of MapFile.Reader.get() works but a second call fails.
>>
>> Also I am getting different exceptions depending on number of entries
>> in a map file.
>> With LzoCodec and 10 record file, jvm gets aborted.
>>
>> At the same time the DefaultCodec works fine for all cases, as well as
>> record compression for the native codecs.
>>
>> I created a simple test program (attached) that creates map files
>> locally with sizes of 10 and 100 records for three codecs: Default,
>> Snappy, and LZO.
>> (The test requires corresponding native library available)
>>
>> The summary of problems are given below:
>>
>> Map Size: 100
>> Compression: RECORD
>> ==================
>> DefaultCodec: OK
>> SnappyCodec: OK
>> LzoCodec: OK
>>
>> Map Size: 10
>> Compression: RECORD
>> ==================
>> DefaultCodec: OK
>> SnappyCodec: OK
>> LzoCodec: OK
>>
>> Map Size: 100
>> Compression: BLOCK
>> ================
>> DefaultCodec: OK
>>
>> SnappyCodec: java.io.EOFException at
>> org.apache.hadoop.io.compress.BlockDecompressorStream.getCompressedData(BlockDecompressorStream.java:114)
>>
>> LzoCodec: java.io.EOFException at
>> org.apache.hadoop.io.compress.BlockDecompressorStream.getCompressedData(BlockDecompressorStream.java:114)
>>
>> Map Size: 10
>> Compression: BLOCK
>> ==================
>> DefaultCodec: OK
>>
>> SnappyCodec: java.lang.NoClassDefFoundError: Ljava/lang/InternalError
>> at
>> org.apache.hadoop.io.compress.snappy.SnappyDecompressor.decompressBytesDirect(Native
>> Method)
>>
>> LzoCodec:
>> #
>> # A fatal error has been detected by the Java Runtime Environment:
>> #
>> # SIGSEGV (0xb) at pc=0x00002b068ffcbc00, pid=6385, tid=47304763508496
>> #
>> # JRE version: 6.0_21-b07
>> # Java VM: Java HotSpot(TM) 64-Bit Server VM (17.0-b17 mixed mode
>> linux-amd64 )
>> # Problematic frame:
>> # C [liblzo2.so.2+0x13c00] lzo1x_decompress+0x1a0
>> #
>> # An error report file with more information is saved as:
>> # /hadoop/user/yurgis/testapp/hs_err_pid6385.log
>> #
>> # If you would like to submit a bug report, please visit:
>> # http://java.sun.com/webapps/bugreport/crash.jsp
>> # The crash happened outside the Java Virtual Machine in native code.
>> # See problematic frame for where to report the bug.
>> #
>
>
>
> --
> Todd Lipcon
> Software Engineer, Cloudera
>
