Author: olga
Date: Tue Dec 1 21:49:16 2009
New Revision: 885956
URL: http://svn.apache.org/viewvc?rev=885956&view=rev
Log:
PIG-978: MQ docs update (chandec via olgan)
Modified:
hadoop/pig/branches/branch-0.6/CHANGES.txt
hadoop/pig/branches/branch-0.6/src/docs/src/documentation/content/xdocs/piglatin_users.xml
Modified: hadoop/pig/branches/branch-0.6/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hadoop/pig/branches/branch-0.6/CHANGES.txt?rev=885956&r1=885955&r2=885956&view=diff
==============================================================================
--- hadoop/pig/branches/branch-0.6/CHANGES.txt (original)
+++ hadoop/pig/branches/branch-0.6/CHANGES.txt Tue Dec 1 21:49:16 2009
@@ -24,6 +24,8 @@
IMPROVEMENTS
+PIG-978: MQ docs update (chandec via olgan)
+
PIG-872: use distributed cache for the replicated data set in FR join
(sriranjan via olgan)
Modified:
hadoop/pig/branches/branch-0.6/src/docs/src/documentation/content/xdocs/piglatin_users.xml
URL:
http://svn.apache.org/viewvc/hadoop/pig/branches/branch-0.6/src/docs/src/documentation/content/xdocs/piglatin_users.xml?rev=885956&r1=885955&r2=885956&view=diff
==============================================================================
---
hadoop/pig/branches/branch-0.6/src/docs/src/documentation/content/xdocs/piglatin_users.xml
(original)
+++
hadoop/pig/branches/branch-0.6/src/docs/src/documentation/content/xdocs/piglatin_users.xml
Tue Dec 1 21:49:16 2009
@@ -385,11 +385,14 @@
<section>
<title>Implicit Dependencies</title>
-<p>If a script has dependencies on the execution order outside of what Pig
knows about, execution may fail. For instance, in this script
-MYUDF might try to read from out1, a file that A was just stored into.
+<p>If a script has dependencies on the execution order outside of what Pig
knows about, execution may fail. </p>
+
+
+<section>
+ <title>Example</title>
+<p>In this script, MYUDF might try to read from out1, a file that A was just
stored into.
However, Pig does not know that MYUDF depends on the out1 file and might
submit the jobs
-producing the out2 and out1 files at the same time.
-</p>
+producing the out2 and out1 files at the same time.</p>
<source>
...
STORE A INTO 'out1';
@@ -410,6 +413,62 @@
STORE C INTO 'out2';
</source>
</section>
+
+<section>
+ <title>Example</title>
+<p>In this script, the store/load operators have different file paths;
however, the load operator depends on the store operator.</p>
+<source>
+A = LOAD '/user/xxx/firstinput' USING PigStorage();
+B = group ....
+C = .... agrregation function
+STORE C INTO '/user/vxj/firstinputtempresult/days1';
+..
+Atab = LOAD '/user/xxx/secondinput' USING PigStorage();
+Btab = group ....
+Ctab = .... agrregation function
+STORE Ctab INTO '/user/vxj/secondinputtempresult/days1';
+..
+E = LOAD '/user/vxj/firstinputtempresult/' USING PigStorage();
+F = group ....
+G = .... aggregation function
+STORE G INTO '/user/vxj/finalresult1';
+
+Etab =LOAD '/user/vxj/secondinputtempresult/' USING PigStorage();
+Ftab = group ....
+Gtab = .... aggregation function
+STORE Gtab INTO '/user/vxj/finalresult2';
+</source>
+
+<p>To make the script works, add the exec statement. </p>
+
+<source>
+A = LOAD '/user/xxx/firstinput' USING PigStorage();
+B = group ....
+C = .... agrregation function
+STORE C INTO '/user/vxj/firstinputtempresult/days1';
+..
+Atab = LOAD '/user/xxx/secondinput' USING PigStorage();
+Btab = group ....
+Ctab = .... agrregation function
+STORE Ctab INTO '/user/vxj/secondinputtempresult/days1';
+
+EXEC;
+
+E = LOAD '/user/vxj/firstinputtempresult/' USING PigStorage();
+F = group ....
+G = .... aggregation function
+STORE G INTO '/user/vxj/finalresult1';
+..
+Etab =LOAD '/user/vxj/secondinputtempresult/' USING PigStorage();
+Ftab = group ....
+Gtab = .... aggregation function
+STORE Gtab INTO '/user/vxj/finalresult2';
+</source>
+
+
+</section>
+</section>
+
</section>
<!-- END MULTI-QUERY EXECUTION-->
