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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/LanguageManual/Locks" by NamitJain
Date Tue, 12 Apr 2011 01:25:57 GMT
Dear Wiki user,

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

The "Hive/LanguageManual/Locks" page has been changed by NamitJain.
http://wiki.apache.org/hadoop/Hive/LanguageManual/Locks?action=diff&rev1=1&rev2=2

--------------------------------------------------

- Describe Hive/LanguageManual/Locks here.
+ <<TableOfContents>>
  
+ == Locks ==
+ 
+ Right now hive can support the following locks:
+  * SHARED
+  * EXCLUSIVE
+ 
+ 
+ One is {{{INPUT__FILE__NAME}}}, which is the input file's name for a mapper task.
+ 
+ 
+ the other is {{{BLOCK__OFFSET__INSIDE__FILE}}}, which is the current global file position.

+ 
+ For block compressed file, it is the current block's file offset, which is the current block's
first byte's file offset.
+ 
+ === Simple Examples ===
+ 
+ select {{{INPUT__FILE__NAME}}}, key, {{{BLOCK__OFFSET__INSIDE__FILE}}} from src;
+ 
+ select key, count({{{INPUT__FILE__NAME}}}) from src group by key order by key;
+ 
+ select * from src where {{{BLOCK__OFFSET__INSIDE__FILE}}} > 12000 order by key;
+ 

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