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stack commented on HBASE-4608: ------------------------------ bq. I noticed the size of sv4r25s8%3A60020.1331661889339.decompressed is different from that of sv4r25s8%3A60020.1331661889339 Because it has metadata the original doesn't have. When I compress it, it compresses down to same size. Notice that the decompressed and decompressed.again are same size because they both have the new meata data. bq. The sentence involving COMPRESSION_VERSION was in past tense but I don't see it in patch v23. Pardon me. Should have uploaded v24. Testing has turned up a minor issue... will upload v25 soon. bq. In my opinion, this version corresponds to the major version in my comment @ 13/Mar/12 01:37 Nope. This is the global version that introduces compression. No need of major/minor granularity, and in particular major/minor on the compression feature itself. Its overkill. bq. I agree that both version and compression type should be checked. However, the order should be checking compression type followed by checking version. Nope. First figure if we have a file that does compression. Then figure what type of compression the file does. > 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, 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. -- 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