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https://issues.apache.org/jira/browse/HBASE-1512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13018703#comment-13018703
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jirapos...@reviews.apache.org commented on HBASE-1512:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/585/
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(Updated 2011-04-12 04:28:32.453024)
Review request for hbase and Gary Helmling.
Changes
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Switched to CoprocessorHost.REGION_COPROCESSOR_CONF_KEY and removed the manual
loading of CPs.
Summary
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This patch provides reference implementation for aggregate function support
through Coprocessor framework.
ColumnInterpreter interface allows client to specify how the value's byte array
is interpreted.
Some of the thoughts are summarized at
http://zhihongyu.blogspot.com/2011/03/genericizing-endpointcoprocessor.html
Himanshu Vashishtha started the work. I provided some review comments and some
of the code.
This addresses bug HBASE-1512.
https://issues.apache.org/jira/browse/HBASE-1512
Diffs (updated)
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/src/main/java/org/apache/hadoop/hbase/client/coprocessor/AggregationClient.java
PRE-CREATION
/src/main/java/org/apache/hadoop/hbase/client/coprocessor/LongColumnInterpreter.java
PRE-CREATION
/src/main/java/org/apache/hadoop/hbase/coprocessor/AggregateCpProtocol.java
PRE-CREATION
/src/main/java/org/apache/hadoop/hbase/coprocessor/AggregateProtocolImpl.java
PRE-CREATION
/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
PRE-CREATION
/src/test/java/org/apache/hadoop/hbase/coprocessor/TestAggFunctions.java
PRE-CREATION
Diff: https://reviews.apache.org/r/585/diff
Testing
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TestAggFunctions passes.
Thanks,
Ted
> 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.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.
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