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https://issues.apache.org/jira/browse/HBASE-823?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12671562#action_12671562
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Luo Ning commented on HBASE-823:
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i think we need archiving 2 goals for the 'open reader limit':
1. fit xceiverCount limitation of hadoop, see HBASE-24
2. control memory usage of mapfile indexes.
we may got 2 by control 'concurrent open readers', but it is not efficient.
because mapfile index size is very different. for regionserver stable, we
should make sure 'open file limit' * 'max mapfile index size' < 'memory limit
of regionserver'. this mean we have to set the 'open file limit' low enough.
so besides 'open reader limit', there should a 'max index size limit' for
concurrent mapfile reader controlling. the eviction policy should considering
these 2 limitation together.
> Concurrent "open mapfile reader" limit
> --------------------------------------
>
> Key: HBASE-823
> URL: https://issues.apache.org/jira/browse/HBASE-823
> Project: Hadoop HBase
> Issue Type: Improvement
> Reporter: stack
> Priority: Blocker
> Fix For: 0.20.0
>
>
> Over in HBASE-745, Luo Ning profiling found that the number of open Readers
> has direct impact on memory used. This issue is about putting an upper bound
> on the number of open Readers doing something like a bounded pool w/ a LRU
> eviction policy.
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