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https://issues.apache.org/jira/browse/HBASE-4608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13224786#comment-13224786
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Zhihong Yu commented on HBASE-4608:
-----------------------------------
I saw this in region server log:
{code}
2012-03-07 13:01:12,408 INFO wal.SequenceFileLogWriter
(SequenceFileLogWriter.java:init(91)) <<regionserver60020.logRoller>> - WAL
compression enabled for
hdfs://sea-lab-0:54310/hbase/.logs/sea-lab-5,60020,1331150872956/sea-lab-5%2C60020%2C1331150872956.1331154072399
{code}
After copying the HLog to local, I issued:
{code}
bin/hbase org.apache.hadoop.hbase.regionserver.wal.Compressor -u
sea-lab-5%2C60020%2C1331150872956.1331154072399 sea-lab-5.decomp
{code}
I got:
{code}
-rwxr-xr-x 1 hduser hduser 119487372 2012-03-07 14:12 sea-lab-5.decomp
-rw-r--r-- 1 hduser hduser 120660017 2012-03-07 14:11
sea-lab-5%2C60020%2C1331150872956.1331154072399
{code}
When I issued compression command, I saw:
{code}
$ bin/hbase org.apache.hadoop.hbase.regionserver.wal.Compressor -c
sea-lab-5.decomp sea-lab-5.comp
12/03/07 14:14:17 INFO wal.SequenceFileLogReader: Input stream class:
org.apache.hadoop.fs.ChecksumFileSystem$ChecksumFSInputChecker, not adjusting
length
12/03/07 14:14:17 INFO wal.SequenceFileLogWriter: WAL compression enabled for
sea-lab-5.comp
12/03/07 14:14:17 DEBUG wal.SequenceFileLogWriter: new createWriter --
HADOOP-6840 -- not available
12/03/07 14:14:17 WARN util.NativeCodeLoader: Failed to load native-hadoop with
error: java.lang.UnsatisfiedLinkError: no hadoop in java.library.path
12/03/07 14:14:17 WARN util.NativeCodeLoader:
java.library.path=/apache/hbase/bin/../lib/native/Linux-amd64-64
12/03/07 14:14:17 WARN util.NativeCodeLoader: Unable to load native-hadoop
library for your platform... using builtin-java classes where applicable
12/03/07 14:14:17 INFO compress.CodecPool: Got brand-new compressor [.deflate]
12/03/07 14:14:17 DEBUG wal.SequenceFileLogWriter: Path=sea-lab-5.comp,
syncFs=true, hflush=true
Exception in thread "main" java.io.IOException: sea-lab-5.decomp,
entryStart=124, pos=1406386, end=119487372, edit=0
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at
org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader.addFileInfoToException(SequenceFileLogReader.java:275)
at
org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader.next(SequenceFileLogReader.java:231)
at
org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader.next(SequenceFileLogReader.java:200)
at
org.apache.hadoop.hbase.regionserver.wal.Compressor.transformFile(Compressor.java:93)
at
org.apache.hadoop.hbase.regionserver.wal.Compressor.main(Compressor.java:59)
Caused by: java.io.IOException: //0 read 36 bytes, should read 22
at org.apache.hadoop.io.SequenceFile$Reader.next(SequenceFile.java:2118)
at org.apache.hadoop.io.SequenceFile$Reader.next(SequenceFile.java:2155)
at
org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader.next(SequenceFileLogReader.java:229)
... 3 more
{code}
> HLog Compression
> ----------------
>
> Key: HBASE-4608
> URL: https://issues.apache.org/jira/browse/HBASE-4608
> Project: HBase
> Issue Type: New Feature
> Reporter: Li Pi
> Assignee: Li Pi
> Fix For: 0.94.0
>
> Attachments: 4608-v19.txt, 4608v1.txt, 4608v13.txt, 4608v13.txt,
> 4608v14.txt, 4608v15.txt, 4608v16.txt, 4608v17.txt, 4608v18.txt, 4608v5.txt,
> 4608v6.txt, 4608v7.txt, 4608v8fixed.txt
>
>
> The current bottleneck to HBase write speed is replicating the WAL appends
> across different datanodes. We can speed up this process by compressing the
> HLog. Current plan involves using a dictionary to compress table name, region
> id, cf name, and possibly other bits of repeated data. Also, HLog format may
> be changed in other ways to produce a smaller HLog.
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