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https://issues.apache.org/jira/browse/HBASE-11573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14071169#comment-14071169
]
stack commented on HBASE-11573:
-------------------------------
Here is what the JSON looks like:
Notice new ageAtEviction and further down, ageInCache:
{code}
[ {
"stats" : {
"iohitsPerSecond" : 59,
"iotimePerHit" : 0.04556650295853615,
"ageAtEvictionSnapshot" : {
"stdDev" : 1.700245315377154E10,
"max" : 1.74233091E11,
"98thPercentile" : 1.2401433921999997E11,
"999thPercentile" : 1.5660392146600003E11,
"min" : 4.8615319E10,
"mean" : 7.24927112239062E10,
"75thPercentile" : 8.051437975E10,
"95thPercentile" : 1.0803019305E11,
"99thPercentile" : 1.3064888673000003E11
},
"missCount" : 71660,
"missCachingCount" : 71660,
"missRatio" : 0.09609788656234741,
"missCachingRatio" : 0.09609788656234741,
"sumHitCountsPastNPeriods" : 0,
"sumRequestCountsPastNPeriods" : 0,
"sumHitCachingCountsPastNPeriods" : 0,
"sumRequestCachingCountsPastNPeriods" : 0,
"hitRatioPastNPeriods" : 0.0,
"hitCachingRatioPastNPeriods" : 0.0,
"requestCount" : 745698,
"hitCount" : 674038,
"hitRatio" : 0.9039021134376526,
"requestCachingCount" : 745698,
"hitCachingCount" : 674038,
"hitCachingRatio" : 0.9039021134376526,
"evictionCount" : 6462,
"evictedCount" : 63540
},
"freeSize" : 25255936,
"currentSize" : 6262784,
"blockCount" : 7083,
"blockCaches" : null,
"maxSize" : 33554432,
"ioEngine" : "ioengine=ByteBufferIOEngine, capacity=33,554,432, direct=true",
"realCacheSize" : 5532627,
"failedBlockAdditions" : 1016,
"allocator" : {
"totalSize" : 31518720,
"buckets" : [ {
"itemAllocationSize" : 5120,
"freeBytes" : 2099200,
"usedBytes" : 0,
"baseOffset" : 0
}, {
"itemAllocationSize" : 9216,
"freeBytes" : 2101248,
"usedBytes" : 0,
"baseOffset" : 2101248
}, {
"itemAllocationSize" : 17408,
"freeBytes" : 2088960,
"usedBytes" : 0,
"baseOffset" : 4202496
}, {
"itemAllocationSize" : 33792,
"freeBytes" : 2095104,
"usedBytes" : 0,
"baseOffset" : 6303744
}, {
"itemAllocationSize" : 41984,
"freeBytes" : 2099200,
"usedBytes" : 0,
"baseOffset" : 8404992
}, {
"itemAllocationSize" : 50176,
"freeBytes" : 2007040,
"usedBytes" : 50176,
"baseOffset" : 10506240
}, {
"itemAllocationSize" : 58368,
"freeBytes" : 2101248,
"usedBytes" : 0,
"baseOffset" : 12607488
}, {
"itemAllocationSize" : 66560,
"freeBytes" : 0,
"usedBytes" : 2063360,
"baseOffset" : 14708736
}, {
"itemAllocationSize" : 99328,
"freeBytes" : 0,
"usedBytes" : 2085888,
"baseOffset" : 16809984
}, {
"itemAllocationSize" : 132096,
"freeBytes" : 1981440,
"usedBytes" : 0,
"baseOffset" : 18911232
}, {
"itemAllocationSize" : 197632,
"freeBytes" : 1976320,
"usedBytes" : 0,
"baseOffset" : 21012480
}, {
"itemAllocationSize" : 263168,
"freeBytes" : 1842176,
"usedBytes" : 0,
"baseOffset" : 23113728
}, {
"itemAllocationSize" : 394240,
"freeBytes" : 1971200,
"usedBytes" : 0,
"baseOffset" : 25214976
}, {
"itemAllocationSize" : 66560,
"freeBytes" : 0,
"usedBytes" : 2063360,
"baseOffset" : 27316224
}, {
"itemAllocationSize" : 525312,
"freeBytes" : 2101248,
"usedBytes" : 0,
"baseOffset" : 29417472
} ]
}
}, {
"size" : 5532627,
"full" : false,
"ageInCacheSnapshot" : {
"stdDev" : 1.967629468474853E10,
"max" : 6.546083E10,
"98thPercentile" : 5.9418365039999985E10,
"999thPercentile" : 6.546083E10,
"min" : -397000.0,
"mean" : 1.3676657147751606E10,
"75thPercentile" : 2.8384937E10,
"95thPercentile" : 5.39450136E10,
"99thPercentile" : 6.464702119999999E10
},
"dataCount" : 0,
"dataSize" : 0,
"count" : 84
} ]
{code}
> Report age on eviction
> ----------------------
>
> Key: HBASE-11573
> URL: https://issues.apache.org/jira/browse/HBASE-11573
> Project: HBase
> Issue Type: Sub-task
> Components: BlockCache
> Reporter: stack
> Assignee: stack
> Attachments: 11573.txt, Screen Shot 2014-07-22 at 5.17.27 PM.png
>
>
> From the parent issue, Todd reminds us of the old Jim Gray '5 minute rule' on
> whether to cache.
> In master, we were reporting age only it was the inactionable inverse of 'how
> long blocks are staying in the cache'.
> Let me add to our cache stats a histogram of age on eviction and change the
> UI reporting so it is age at eviction (plus stddev). The JSON version has
> percentiles (and if wanted, the old age report of age of items in cache).
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