readBlock in HFile.Reader not 64 KB, but 5~6MB
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Key: HBASE-4111
URL: https://issues.apache.org/jira/browse/HBASE-4111
Project: HBase
Issue Type: Bug
Components: io, regionserver
Reporter: mingjian
Assignee: mingjian
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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