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https://issues.apache.org/jira/browse/HIVE-556?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12719518#action_12719518
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Min Zhou commented on HIVE-556:
-------------------------------
I didn't see any filter there, hive will put all fields of my small table into
HTree.
{noformat}
hive>explain select /*+ MAPJOIN(a) */ a.url_pattern, w.url from application a
join web_log w where w.logdate='20090611' and w.url rlike a.url_pattern and
a.dt='20090609';
Common Join Operator
condition map:
Inner Join 0 to 1
condition expressions:
0 {bussiness_id} {subclass_id} {class_id} {note} {name}
{url_pattern} {dt}
1....
{noformat}
We only put a.url_pattern into a HashMap in our raw map-reduce implemenation.
> let hive support theta join
> ---------------------------
>
> Key: HIVE-556
> URL: https://issues.apache.org/jira/browse/HIVE-556
> Project: Hadoop Hive
> Issue Type: New Feature
> Affects Versions: 0.4.0
> Reporter: Min Zhou
> Fix For: 0.4.0
>
>
> Right now , hive only support equal joins . Sometimes it's not enough, we
> must consider implementing theta joins like
> {code:sql}
> SELECT
> a.subid, a.id, t.url
> FROM
> tbl t JOIN aux_tbl a ON t.url rlike a.url_pattern
> WHERE
> t.dt='20090609'
> AND a.dt='20090609';
> {code}
> any condition expression following 'ON' is appropriate.
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