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