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Posted to dev@hbase.apache.org by "Andrew Purtell (JIRA)" <ji...@apache.org> on 2009/01/05 20:15:44 UTC
[jira] Updated: (HBASE-1050) Allow regions to split around scanners
[ https://issues.apache.org/jira/browse/HBASE-1050?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Andrew Purtell updated HBASE-1050:
----------------------------------
Priority: Major (was: Blocker)
Fix Version/s: (was: 0.19.0)
0.20.0
A configuration change to dfs.datanode.handler.count from its default of 3 to something much larger has altered overall system behavior on my cluster sufficiently to stop the apparent split suppression by scanning mapreduce jobs that I was seeing.
The core of this issue -- allowing splits around scanners -- is still an important consideration for scalability IMHO.
Moving out of 0.19 and marking down to major.
> Allow regions to split around scanners
> --------------------------------------
>
> Key: HBASE-1050
> URL: https://issues.apache.org/jira/browse/HBASE-1050
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: client, regionserver
> Reporter: Andrew Purtell
> Assignee: stack
> Fix For: 0.20.0
>
>
> We have a number of scanners iterating over a table that also sees a lot of constant write activity. If the scans are too frequent we will suppress splitting. At a lull then a number of splits happen all at once, occasionally overwhelming DFS and causing file corruption.
> I wonder how much work it would be to split regions around scanners. Rather than wait for scanner leases to expire, suspend/block the scanner, split the table, and then negotiate with the client to continue.
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