hadoop-common-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/LanguageManual/LateralView" by PaulYang
Date Fri, 09 Apr 2010 00:26:35 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hive/LanguageManual/LateralView" page has been changed by PaulYang.


  Lateral view is used in conjunction with user-defined table generating functions such as
explode(). As mentioned in [[Hive/LanguageManual/UDF#UDTF]], a UDTF generates one or more
output rows for each input row. A lateral view first applies the UDTF to each row of base
table and then joins resulting output rows to the input rows to form a virtual table having
the supplied table alias. 
+ == Important note ==
+ Currently, there is a bug with lateral views and PPD. If you use a WHERE clause, you may
run into this problem. Look for the fix to come out at [https://issues.apache.org/jira/browse/HIVE-1056]
+ Until then, try adding {{{set hive.optimize.ppd=false;}}} before your query.
  == Example ==
  Consider the following base table named pageAds. It has two columns: pageid (name of the
page) and adid_list (an array of ads appearing on the page):

View raw message