hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "jiraposter@reviews.apache.org (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-4608) HLog Compression
Date Wed, 14 Mar 2012 17:42:44 GMT

    [ https://issues.apache.org/jira/browse/HBASE-4608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13229420#comment-13229420
] 

jiraposter@reviews.apache.org commented on HBASE-4608:
------------------------------------------------------


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/4328/#review5951
-----------------------------------------------------------

Ship it!


Some comments and nits inside. Some extraneous whitespace (can be fixed at commit).


src/main/java/org/apache/hadoop/hbase/regionserver/wal/Compressor.java
<https://reviews.apache.org/r/4328/#comment12915>

    Nit: Comment here that the status byte is the higher order byte of the dict entry.



src/main/java/org/apache/hadoop/hbase/regionserver/wal/Compressor.java
<https://reviews.apache.org/r/4328/#comment12916>

    I assume we're entirely sure that a dictionary will never have > 2^15 entries.



src/main/java/org/apache/hadoop/hbase/regionserver/wal/Compressor.java
<https://reviews.apache.org/r/4328/#comment12914>

    Nit: The naming convention is a bit strange.
    This one is called uncompress... whereas the method returning a new byte[] is called readCompressed



src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLog.java
<https://reviews.apache.org/r/4328/#comment12917>

    Have a constructor that takes a compression context too?
    It seems like once anything has been written to the HLog this should be immutable.



src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogKey.java
<https://reviews.apache.org/r/4328/#comment12919>

    COMPRESSED is a bit of a strange name.
    I happens to be a version of the WAL that supports compression, but it is not necessarily
compressed.



src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogKey.java
<https://reviews.apache.org/r/4328/#comment12920>

    ugly whitespace :)



src/main/java/org/apache/hadoop/hbase/regionserver/wal/LRUDictionary.java
<https://reviews.apache.org/r/4328/#comment12921>

    I think I had that question to Li Pi... How much memory do we expect this dictionary to
take worst case?
    I guess since there is one WAL per region server and it is rolled periodically it is not
a problem at all.



src/main/java/org/apache/hadoop/hbase/regionserver/wal/LRUDictionary.java
<https://reviews.apache.org/r/4328/#comment12922>

    I'll trust you folks that a PriorityQueue would not work here.


- Lars


On 2012-03-14 07:34:58, Michael Stack wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/4328/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2012-03-14 07:34:58)
bq.  
bq.  
bq.  Review request for hbase.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  See issue
bq.  
bq.  
bq.  This addresses bug hbase-4608.
bq.      https://issues.apache.org/jira/browse/hbase-4608
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    src/main/java/org/apache/hadoop/hbase/HConstants.java 045c6f3 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/CompressionContext.java PRE-CREATION

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/Compressor.java PRE-CREATION

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/Dictionary.java PRE-CREATION

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLog.java b5049b1 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogKey.java 311ea1b 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/KeyValueCompression.java PRE-CREATION

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/LRUDictionary.java PRE-CREATION

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogReader.java ff63a5f

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogWriter.java 01ebb5c

bq.    src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALEdit.java d8f317c 
bq.    src/main/java/org/apache/hadoop/hbase/util/Bytes.java de8e40b 
bq.    src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestCompressor.java PRE-CREATION

bq.    src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestKeyValueCompression.java
PRE-CREATION 
bq.    src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestLRUDictionary.java PRE-CREATION

bq.    src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestWALReplay.java a11899c 
bq.    src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestWALReplayCompressed.java
PRE-CREATION 
bq.  
bq.  Diff: https://reviews.apache.org/r/4328/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  Michael
bq.  
bq.


                
> HLog Compression
> ----------------
>
>                 Key: HBASE-4608
>                 URL: https://issues.apache.org/jira/browse/HBASE-4608
>             Project: HBase
>          Issue Type: New Feature
>            Reporter: Li Pi
>            Assignee: stack
>             Fix For: 0.94.0
>
>         Attachments: 4608-v19.txt, 4608-v20.txt, 4608-v22.txt, 4608v1.txt, 4608v13.txt,
4608v13.txt, 4608v14.txt, 4608v15.txt, 4608v16.txt, 4608v17.txt, 4608v18.txt, 4608v23.txt,
4608v24.txt, 4608v25.txt, 4608v27.txt, 4608v5.txt, 4608v6.txt, 4608v7.txt, 4608v8fixed.txt,
hbase-4608-v28-delta.txt, hbase-4608-v28.txt, hbase-4608-v28.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.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message