HBase
  1. HBase
  2. HBASE-8315

Documentation should have more information of LRU Stats

    Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 0.95.0
    • Fix Version/s: 0.99.0
    • Component/s: documentation
    • Labels:

      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?

        Activity

        Hide
        Enis Soztutar added a comment -

        Closing this issue after 0.99.0 release.

        Show
        Enis Soztutar added a comment - Closing this issue after 0.99.0 release.
        Hide
        Daisuke Kobayashi added a comment -
        Show
        Daisuke Kobayashi added a comment - Thanks stack and Misty Stanley-Jones !
        Hide
        Hudson added a comment -

        SUCCESS: Integrated in HBase-TRUNK #5202 (See https://builds.apache.org/job/HBase-TRUNK/5202/)
        HBASE-8315 Documentation should have more information of LRU Stats (stack: rev 492f1f6d44152c11dae4f11eb2b2f20793f964bf)

        • hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon
        Show
        Hudson added a comment - SUCCESS: Integrated in HBase-TRUNK #5202 (See https://builds.apache.org/job/HBase-TRUNK/5202/ ) HBASE-8315 Documentation should have more information of LRU Stats (stack: rev 492f1f6d44152c11dae4f11eb2b2f20793f964bf) hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon
        Hide
        stack added a comment -

        Committed small text change in UI and committed to master.

        Show
        stack added a comment - Committed small text change in UI and committed to master.
        Hide
        stack added a comment -

        Screen shot of what it looks like in the UI

        Show
        stack added a comment - Screen shot of what it looks like in the UI
        Hide
        stack added a comment -

        I just put Daisuke Kobayashi's suggested text into the UI.

        Show
        stack added a comment - I just put Daisuke Kobayashi 's suggested text into the UI.
        Hide
        stack added a comment -

        I can help here Misty Stanley-Jones Let me write something up.

        Show
        stack added a comment - I can help here Misty Stanley-Jones Let me write something up.
        Hide
        Misty Stanley-Jones added a comment -

        Daisuke Kobayashi Do you think this info is still current? Where did you envision it going in the Ref Guide? I couldn't find a place where any of this is discussed currently.

        Show
        Misty Stanley-Jones added a comment - Daisuke Kobayashi Do you think this info is still current? Where did you envision it going in the Ref Guide? I couldn't find a place where any of this is discussed currently.

          People

          • Assignee:
            Misty Stanley-Jones
            Reporter:
            Daisuke Kobayashi
          • Votes:
            0 Vote for this issue
            Watchers:
            9 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

              Development