Andrew Kyle Purtell created HBASE-26353:
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Summary: Support loadable dictionaries in hbase-compression-zstd
Key: HBASE-26353
URL: https://issues.apache.org/jira/browse/HBASE-26353
Project: HBase
Issue Type: Sub-task
Reporter: Andrew Kyle Purtell
Assignee: Andrew Kyle Purtell
Fix For: 2.5.0, 3.0.0-alpha-2
ZStandard supports initialization of compressors and decompressors with a
precomputed dictionary, which can dramatically improve and speed up compression
of tables with small values. For more details, please see [The Case For Small
Data
Compression|https://github.com/facebook/zstd#the-case-for-small-data-compression].
If a table is going to have a lot of small values and the user can put together
a representative set of files that can be used to train a dictionary for
compressing those values, a dictionary can be trained with the {{zstd}} command
line utility, available in any zstandard package for your favorite OS:
Training:
{noformat}
$ zstd --maxdict=1126400 --train-fastcover=shrink \
-o mytable.dict training_files/*
Trying 82 different sets of parameters
...
k=674
d=8
f=20
steps=40
split=75
accel=1
Save dictionary of size 1126400 into file mytable.dict
{noformat}
Deploy the dictionary file to HDFS.
Create the table:
{noformat}
hbase> create "mytable",
... ,
CONFIGURATION => {
'hbase.io.compress.zstd.level' => '6',
'hbase.io.compress.zstd.dictionary' => true,
'hbase.io.compress.zstd.dictonary.file' => \
'hdfs://nn/zdicts/mytable.dict'
}
{noformat}
Now start storing data. Compression results even for small values will be
excellent.
Note: Beware, if the dictionary is lost, the data will not be decompressable.
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