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https://issues.apache.org/jira/browse/HBASE-2468?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12870472#action_12870472
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HBase Review Board commented on HBASE-2468:
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Message from: "Todd Lipcon" <t...@cloudera.com>
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This is an automatically generated e-mail. To reply, visit:
http://review.hbase.org/r/78/
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Review request for hbase.
Summary
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Posting review board for this JIRA on behalf of Mingjie Lai
This addresses bug HBASE-2468.
http://issues.apache.org/jira/browse/HBASE-2468
Diffs
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src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java 09de2ac
src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java 3de661e
src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java 95e494a
Diff: http://review.hbase.org/r/78/diff
Testing
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Thanks,
Todd
> Improvements to prewarm META cache on clients
> ---------------------------------------------
>
> Key: HBASE-2468
> URL: https://issues.apache.org/jira/browse/HBASE-2468
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: client
> Reporter: Todd Lipcon
> Assignee: Mingjie Lai
> Fix For: 0.21.0
>
> Attachments: HBASE-2468-trunk.patch
>
>
> A couple different use cases cause storms of reads to META during startup.
> For example, a large MR job will cause each map task to hit meta since it
> starts with an empty cache.
> A couple possible improvements have been proposed:
> - MR jobs could ship a copy of META for the table in the DistributedCache
> - Clients could prewarm cache by doing a large scan of all the meta for the
> table instead of random reads for each miss
> - Each miss could fetch ahead some number of rows in META
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