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https://issues.apache.org/jira/browse/HBASE-4608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13150139#comment-13150139
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jirapos...@reviews.apache.org commented on HBASE-4608:
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bq. On 2011-11-09 20:00:52, Nicolas Spiegelberg wrote:
bq. > src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALEdit.java,
lines 122-124
bq. > <https://reviews.apache.org/r/2740/diff/1/?file=56624#file56624line122>
bq. >
bq. > should compression be added to the HLogKey as well to compress
regionName & table? It seems like the biggest wins will come from table +
region + family, which all have user-bounded values. It might even make sense
to have these values in a different dictionary from row & column qualifier,
which can be unbounded and might accidentally dominate the dictionary
bq.
bq. Li Pi wrote:
bq. Yes. I'm adding compression for regionname, table, and family as well.
For this kind of simple 1 way associative dictionary, its likely that those two
factors will end up dominating, but other more complex dictionaries can be
used, perhaps with more interesting eviction strategies.
bq.
bq. I do agree using multiple dictionaries is a simple strategy.
FYI I already compress CF name along with column qualifier. Are regionname and
table stored as part of the row key?
- Li
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On 2011-11-07 23:12:37, Li Pi wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/2740/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-11-07 23:12:37)
bq.
bq.
bq. Review request for hbase, Eli Collins and Todd Lipcon.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. Heres what I have so far. Things are written, and "should work". I need to
rework the test cases to test this, and put something in the config file to
enable/disable. Obviously this isn't ready for commit at the moment, but I can
get those two things done pretty quickly.
bq.
bq. Obviously the dictionary is incredibly simple at the moment, I'll come up
with something cooler sooner. Let me know how this looks.
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/KeyValue.java e68e486
bq.
src/main/java/org/apache/hadoop/hbase/regionserver/wal/CompressedKeyValue.java
PRE-CREATION
bq.
src/main/java/org/apache/hadoop/hbase/regionserver/wal/SimpleDictionary.java
PRE-CREATION
bq.
src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALDictionary.java
PRE-CREATION
bq. src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALEdit.java
e1117ef
bq.
bq. Diff: https://reviews.apache.org/r/2740/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq.
bq. Thanks,
bq.
bq. Li
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: Li Pi
> Attachments: 4608v1.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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