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https://issues.apache.org/jira/browse/HBASE-4111?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13068752#comment-13068752
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Li Pi commented on HBASE-4111:
------------------------------
Ran complete test.
2011-07-20 18:16:10,070 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache:
LRU Stats: total=79.46 MB, free=19.29 MB, max=98.75 MB, blocks=1255,
accesses=5085601, hits=2477127, hitRatio=48.70%%, cachingAccesses=5085597,
cachingHits=2477127, cachingHitsRatio=48.70%%, evictions=16501,
evicted=2607215, evictedPerRun=158.00344848632812
CacheSize set to 0.1 of heapsize. Made sure it was hitting disk for most of
writes.
Bug can't be reproduced. Though my testload merely has a bunch of very small
files.
> readBlock in HFile.Reader not 64 KB, but 5~6MB
> ----------------------------------------------
>
> Key: HBASE-4111
> URL: https://issues.apache.org/jira/browse/HBASE-4111
> Project: HBase
> Issue Type: Bug
> Components: io, regionserver
> Reporter: mingjian
> Assignee: Li Pi
> Attachments: code and result.txt
>
>
> We found a strange problem in our read test.
> It is a 5 nodes cluster.Four of our 5 regionservers set
> "hfile.block.cache.size"=0.4, one of them is 0.1(we call it node A). When we
> random read from a 2TB data table we found node A's network reached 100MB,
> and others are less than 10MB. So the read speed is low.
> We set node A's "hfile.block.cache.size"=0.2, then all the nodes's
> network are 10MB, that's right. To find why is this we debug with btrace and
> find "readBlock" in HFile.Reader become abnormal.We know hbase read a block
> which is 64 KB from disks and put it into blockcache. But when we set
> "hfile.block.cache.size"=0.1, it is not 64KB, it is 5~6MB one time after
> about 1 minute we restart hbase.
> Why not 64 KB? The btrace code and results are in the attachments.
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