[
https://issues.apache.org/jira/browse/HBASE-26398?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Istvan Toth updated HBASE-26398:
--------------------------------
Priority: Minor (was: Major)
> CellCounter fails for large tables filling up local disk
> --------------------------------------------------------
>
> Key: HBASE-26398
> URL: https://issues.apache.org/jira/browse/HBASE-26398
> Project: HBase
> Issue Type: Bug
> Components: mapreduce
> Affects Versions: 3.0.0-alpha-2
> Reporter: Istvan Toth
> Assignee: Istvan Toth
> Priority: Minor
>
> CellCounter dumps all cell coordinates into its output, which can become huge.
> The spill can fill the local disk on the reducer.
> CellCounter hardcodes *mapreduce.job.reduces* to *1*, so it is not possible
> to use multiple reducers to get around this.
> Fixing this is easy, by not hardcoding *mapreduce.job.reduces*, it still
> defaults to 1, but can be overriden by the user.
> CellCounter also generates two extra records with constant keys for each
> cell, which have to be processed by the reducer.
> Even with multiple reducers, these (1/3 of the totcal records) will got the
> same reducer, which can also fill up the disk.
> This can be fixed by adding a Combiner to the Mapper, which sums the counter
> records, thereby reducing the Mapper output records to 1/3 of their previous
> amount.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
