[
https://issues.apache.org/jira/browse/HBASE-1512?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Himanshu Vashishtha updated HBASE-1512:
---------------------------------------
Attachment: patch-1512-8.txt
Changes as per Stack's review.
Major changes include:
a) LongColumnInterpreter still implements Writable (though with empty
read/write methods).
b) Exception is thrown in case of more than one family is defined.
> Coprocessors: Support aggregate functions
> -----------------------------------------
>
> Key: HBASE-1512
> URL: https://issues.apache.org/jira/browse/HBASE-1512
> Project: HBase
> Issue Type: Sub-task
> Components: coprocessors
> Reporter: stack
> Attachments: 1512.zip, AggregateCpProtocol.java,
> AggregateProtocolImpl.java, AggregationClient.java, ColumnInterpreter.java,
> patch-1512-2.txt, patch-1512-3.txt, patch-1512-4.txt, patch-1512-5.txt,
> patch-1512-6.txt, patch-1512-7.txt, patch-1512-8.txt, patch-1512.txt
>
>
> Chatting with jgray and holstad at the kitchen table about counts, sums, and
> other aggregating facility, facility generally where you want to calculate
> some meta info on your table, it seems like it wouldn't be too hard making a
> filter type that could run a function server-side and return the result ONLY
> of the aggregation or whatever.
> For example, say you just want to count rows, currently you scan, server
> returns all data to client and count is done by client counting up row keys.
> A bunch of time and resources have been wasted returning data that we're not
> interested in. With this new filter type, the counting would be done
> server-side and then it would make up a new result that was the count only
> (kinda like mysql when you ask it to count, it returns a 'table' with a count
> column whose value is count of rows). We could have it so the count was
> just done per region and return that. Or we could maybe make a small change
> in scanner too so that it aggregated the per-region counts.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
