Daisuke Kobayashi created HBASE-8315:
----------------------------------------
Summary: Documentation should have more information of LRU Stats
Key: HBASE-8315
URL: https://issues.apache.org/jira/browse/HBASE-8315
Project: HBase
Issue Type: Improvement
Components: documentation
Affects Versions: 0.95.0
Reporter: Daisuke Kobayashi
Unfortunately, there's no documentation to explain the meaning of each LRU
Stats in the regionserver logs. So this is for creating a new paragraph
regarding this. My current idea is below, but it's a little bit difficult to
explain the difference between 'cachingAccesses' and 'accesses' from an
administrator or a user views.
Could you guys help to improve the content?
{noformat}
total: The current memory size of the cache in use.
free: The total free memory currently available to store more cache entries.
max: Maximum allowed memory size of the cache.
blocks: Caches store blocks of data; this number is the current # of blocks
stored, which use up the "total" memory space.
accesses: The total number of times the cache was accessed, regardless of
result.
hits: The total number of times the cache was accessed and the result was a
successful hit (presence of looked up element in cache is a hit).
hitRatio: The current percentage for "hits / accesses".
====
Unclear:
cachingAccesses: cachingHits + The number of getBlock requests that were cache
misses, but only from requests that were set to use the block cache.
cachingHits: The number of getBlock requests that were cache hits, but only
from requests that were set to use the block cache. This is because all reads
=====
cachingHitsRatio: The current percentage for "cachintHits / cachingAccesses"
evictions: The total number of times an eviction has occurred (based on the use
of the LRU algorithm)
evicted: The total number of blocks that have been evicted (based on the use of
the LRU algorithm)
evictedPerRun: The total number of blocks that have been evicted overall / The
number of times an eviction has occurred overall
{noformat}
And also, where should we add this paragraph in the documentation?
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
