Feng Honghua created HBASE-10263:
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Summary: make LruBlockCache single/multi/in-memory ratio
user-configurable and provide preemptive mode for in-memory type block
Key: HBASE-10263
URL: https://issues.apache.org/jira/browse/HBASE-10263
Project: HBase
Issue Type: Improvement
Reporter: Feng Honghua
Assignee: Feng Honghua
Attachments: HBASE-10263-trunk_v0.patch
currently the single/multi/in-memory ratio in LruBlockCache is hardcoded 1:2:1,
which can lead to somewhat counter-intuition behavior for some user scenario
where in-memory table's read performance is much worse than ordinary table when
two tables' data size is almost equal and larger than regionserver's cache size
(we ever did some such experiment and verified that in-memory table random read
performance is two times worse than ordinary table).
this patch fixes above issue and provides:
1. make single/multi/in-memory ratio user-configurable
2. provide a configurable switch which can make in-memory block preemptive, by
preemptive means when this switch is on in-memory block can kick out any
ordinary block to make room until no ordinary block, when this switch is off
(by default) the behavior is the same as previous, using single/multi/in-memory
ratio to determine evicting.
by default, above two changes are both off and the behavior keeps the same as
before applying this patch. it's client/user's choice to determine whether or
which behavior to use by enabling one of these two enhancements.
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