Turn on WAL compression by default
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Key: HBASE-5778
URL: https://issues.apache.org/jira/browse/HBASE-5778
Project: HBase
Issue Type: Improvement
Reporter: Jean-Daniel Cryans
Priority: Blocker
Fix For: 0.94.0, 0.96.0
I ran some tests to verify if WAL compression should be turned on by default.
For a use case where it's not very useful (values two order of magnitude bigger
than the keys), the insert time wasn't different and the CPU usage 15% higher
(150% CPU usage VS 130% when not compressing the WAL).
When values are smaller than the keys, I saw a 38% improvement for the insert
run time and CPU usage was 33% higher (600% CPU usage VS 450%). I'm not sure
WAL compression accounts for all the additional CPU usage, it might just be
that we're able to insert faster and we spend more time in the MemStore per
second (because our MemStores are bad when they contain tens of thousands of
values).
Those are two extremes, but it shows that for the price of some CPU we can save
a lot. My machines have 2 quads with HT, so I still had a lot of idle CPUs.
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