hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Phabricator (Updated) (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-4218) Delta Encoding of KeyValues (aka prefix compression)
Date Wed, 21 Dec 2011 01:47:33 GMT

     [ https://issues.apache.org/jira/browse/HBASE-4218?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Phabricator updated HBASE-4218:
-------------------------------

    Attachment: D447.9.patch

mbautin updated the revision "[jira] [HBASE-4218] HFile data block encoding (delta encoding)".
Reviewers: JIRA, tedyu, stack, nspiegelberg, Kannan

  Addressed new review comments by Kannan and Michael. Also changed the terminology, replacing
"delta encoding" with "data block encoding", as Matt and Ted suggested. Renamed the "delta
encoding in memory" option to "encoded seek" which is what it really does. As a result of
these changes, the code has moved around considerably.

REVISION DETAIL
  https://reviews.facebook.net/D447

AFFECTED FILES
  src/main/java/org/apache/hadoop/hbase/HColumnDescriptor.java
  src/main/java/org/apache/hadoop/hbase/KeyValue.java
  src/main/java/org/apache/hadoop/hbase/io/HalfStoreFileReader.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/BitsetKeyDeltaEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/BufferedDataBlockEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/CompressionState.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/CopyKeyDataBlockEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/DataBlockEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/DataBlockEncodingAlgorithms.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/DiffKeyDeltaEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/EncodedDataBlock.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/EncoderBufferTooSmallException.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/FastDiffDeltaEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/encoding/PrefixKeyDeltaEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/AbstractHFileReader.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/AbstractHFileWriter.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/BlockType.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlockIndex.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileDataBlockEncoder.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileDataBlockEncoderImpl.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderV1.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderV2.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileWriterV1.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/HFileWriterV2.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java
  src/main/java/org/apache/hadoop/hbase/io/hfile/NoOpDataBlockEncoder.java
  src/main/java/org/apache/hadoop/hbase/mapreduce/LoadIncrementalHFiles.java
  src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
  src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java
  src/main/java/org/apache/hadoop/hbase/regionserver/Store.java
  src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java
  src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileScanner.java
  src/main/java/org/apache/hadoop/hbase/regionserver/metrics/SchemaConfigured.java
  src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java
  src/main/ruby/hbase/admin.rb
  src/test/java/org/apache/hadoop/hbase/HBaseTestCase.java
  src/test/java/org/apache/hadoop/hbase/HFilePerformanceEvaluation.java
  src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java
  src/test/java/org/apache/hadoop/hbase/io/TestHalfStoreFileReader.java
  src/test/java/org/apache/hadoop/hbase/io/TestHeapSize.java
  src/test/java/org/apache/hadoop/hbase/io/encoding/RedundantKVGenerator.java
  src/test/java/org/apache/hadoop/hbase/io/encoding/TestBufferedDataBlockEncoder.java
  src/test/java/org/apache/hadoop/hbase/io/encoding/TestDataBlockEncoders.java
  src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java
  src/test/java/org/apache/hadoop/hbase/io/hfile/TestCacheOnWrite.java
  src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileBlock.java
  src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileBlockIndex.java
  src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileDataBlockEncoder.java
  src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileWriterV2.java
  src/test/java/org/apache/hadoop/hbase/mapreduce/TestImportExport.java
  src/test/java/org/apache/hadoop/hbase/regionserver/CreateRandomStoreFile.java
  src/test/java/org/apache/hadoop/hbase/regionserver/DataBlockEncodingTool.java
  src/test/java/org/apache/hadoop/hbase/regionserver/EncodedSeekPerformanceTest.java
  src/test/java/org/apache/hadoop/hbase/regionserver/TestCompactSelection.java
  src/test/java/org/apache/hadoop/hbase/regionserver/TestCompaction.java
  src/test/java/org/apache/hadoop/hbase/regionserver/TestCompoundBloomFilter.java
  src/test/java/org/apache/hadoop/hbase/regionserver/TestFSErrorsExposed.java
  src/test/java/org/apache/hadoop/hbase/regionserver/TestStoreFile.java
  src/test/java/org/apache/hadoop/hbase/util/TestByteBufferUtils.java

                
> Delta Encoding of KeyValues  (aka prefix compression)
> -----------------------------------------------------
>
>                 Key: HBASE-4218
>                 URL: https://issues.apache.org/jira/browse/HBASE-4218
>             Project: HBase
>          Issue Type: Improvement
>          Components: io
>    Affects Versions: 0.94.0
>            Reporter: Jacek Migdal
>            Assignee: Mikhail Bautin
>              Labels: compression
>         Attachments: 0001-Delta-encoding-fixed-encoded-scanners.patch, D447.1.patch,
D447.2.patch, D447.3.patch, D447.4.patch, D447.5.patch, D447.6.patch, D447.7.patch, D447.8.patch,
D447.9.patch, Delta_encoding_with_memstore_TS.patch, open-source.diff
>
>
> A compression for keys. Keys are sorted in HFile and they are usually very similar. Because
of that, it is possible to design better compression than general purpose algorithms,
> It is an additional step designed to be used in memory. It aims to save memory in cache
as well as speeding seeks within HFileBlocks. It should improve performance a lot, if key
lengths are larger than value lengths. For example, it makes a lot of sense to use it when
value is a counter.
> Initial tests on real data (key length = ~ 90 bytes , value length = 8 bytes) shows that
I could achieve decent level of compression:
>  key compression ratio: 92%
>  total compression ratio: 85%
>  LZO on the same data: 85%
>  LZO after delta encoding: 91%
> While having much better performance (20-80% faster decompression ratio than LZO). Moreover,
it should allow far more efficient seeking which should improve performance a bit.
> It seems that a simple compression algorithms are good enough. Most of the savings are
due to prefix compression, int128 encoding, timestamp diffs and bitfields to avoid duplication.
That way, comparisons of compressed data can be much faster than a byte comparator (thanks
to prefix compression and bitfields).
> In order to implement it in HBase two important changes in design will be needed:
> -solidify interface to HFileBlock / HFileReader Scanner to provide seeking and iterating;
access to uncompressed buffer in HFileBlock will have bad performance
> -extend comparators to support comparison assuming that N first bytes are equal (or some
fields are equal)
> Link to a discussion about something similar:
> http://search-hadoop.com/m/5aqGXJEnaD1/hbase+windows&subj=Re+prefix+compression

--
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