Details
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Improvement
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Status: Closed
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Major
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Resolution: Fixed
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0.95.0
Description
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?
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
And also, where should we add this paragraph in the documentation?