Thomas Mueller created OAK-1042:
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Summary: Segment node store caching
Key: OAK-1042
URL: https://issues.apache.org/jira/browse/OAK-1042
Project: Jackrabbit Oak
Issue Type: Improvement
Reporter: Thomas Mueller
Assignee: Thomas Mueller
Segment node stores caching seems to use quite a lot of CPU. According to my
test, the oak-run SimpleSearchTest uses about 50% for Segment node store
caching, when using the built-in profiler:
{code}
java -mx1g -Dwarmup=3 -Druntime=15 -jar target/oak-run-*.jar benchmark
SimpleSearchTest Oak-Tar
packages:
48%: com.google.common.cache <== cache
16%: org.apache.jackrabbit.oak.plugins.segment
8%: org.apache.jackrabbit.oak.plugins.memory
4%: org.apache.jackrabbit.oak.util
3%: org.apache.jackrabbit.oak.core
2%: org.apache.jackrabbit.oak.benchmark
2%: com.google.common.base <== cache
.
Oak-Tar 308 310 313 324 344 48
{code}
The problem seems to be the cache in the FileStore. As far as I see, the cache
limit is 1000 <UUID, Segment> entries (size based, not weight based).
I wonder if there is a simple way to reduce CPU usage. I will try with the LIRS
cache.
I also wonder if this cache should really be size limited, and not weight
limited (segments can have different sizes as far as I know)?
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