Andrew Purtell created HBASE-22114:
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Summary: Port HBASE-15560 (TinyLFU-based BlockCache) to branch-1
Key: HBASE-22114
URL: https://issues.apache.org/jira/browse/HBASE-22114
Project: HBase
Issue Type: Sub-task
Reporter: Andrew Purtell
Fix For: 1.6.0
HBASE-15560 introduces the TinyLFU cache policy for the blockcache.
W-TinyLFU ([research paper|http://arxiv.org/pdf/1512.00727.pdf]) records the
frequency in a counting sketch, ages periodically by halving the counters, and
orders entries by SLRU. An entry is discarded by comparing the frequency of the
new arrival (candidate) to the SLRU's victim, and keeping the one with the
highest frequency. This allows the operations to be performed in O(1) time and,
though the use of a compact sketch, a much larger history is retained beyond
the current working set. In a variety of real world traces the policy had [near
optimal hit rates|https://github.com/ben-manes/caffeine/wiki/Efficiency].
The implementation of HBASE-15560 uses several Java 8 idioms, depends on JRE 8+
type Optional, and has dependencies on libraries compiled with Java 8+
bytecode. It could be backported to branch-1 but must be made optional both at
compile time and runtime, enabled by the 'build-with-jdk8' build profile. To
this end the blockcache should be slightly modified to load L1 (and perhaps L2)
implementation/policy dynamically at startup by reflection, with implementation
classname specified in site configuration. This modification should be forward
ported to maintain configuration sanity among the branches.
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