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Peter Marron 2012-10-23, 12:44
Hi Peter,

Indexing support was added to Hive in 0.7 and in 0.8 the query compiler was
enhanced to optimized some class of queries (certain group bys and joins)
using indexes. Assuming you are using the built in index handler you need
to do the following _after_ you have created and rebuilt the index,

SET hive.index.compact.file='/tmp/index_result';
SET
hive.input.format=org.apache.hadoop.hive.ql.index.compact.HiveCompactIndexInputFormat;

You will then notice speed up for a query of the form,

select count(*) from tab where indexed_col = some_val

Thanks,
Shreepadma

On Tue, Oct 23, 2012 at 5:44 AM, Peter Marron <
[EMAIL PROTECTED]> wrote:

>  Hi,****
>
> ** **
>
> I’m very much a Hive newbie but I’ve been looking at HIVE-417 and this
> page in particular:****
>
> http://cwiki.apache.org/confluence/display/Hive/IndexDev****
>
> Using this information I’ve been able to create an index (using Hive 0.8.1)
> ****
>
> and when I look at the contents it all looks very promising indeed.****
>
> However on the same page there’s this comment:****
>
> ** **
>
> “…This document currently only covers index creation and maintenance. A
> follow-on will explain how indexes are used to optimize queries (building
> on FilterPushdownDev<https://cwiki.apache.org/confluence/display/Hive/FilterPushdownDev>
> )….”****
>
> ** **
>
> However I can’t find the “follow-on” which tells me how to exploit the
> index that I’ve****
>
> created to “optimize” subsequent queries.****
>
> Now I’ve been told that I can create and use indexes with the current****
>
> release of Hive _*without*_ writing and developing any Java code of my
> own.****
>
> Is this true? If so, how?****
>
> ** **
>
> Any help appreciated.****
>
> ** **
>
> Peter Marron.****
>
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Peter Marron 2012-10-24, 12:26
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Shreepadma Venugopalan 2012-10-23, 19:03
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Peter Marron 2014-02-24, 15:00
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB