Unable to resolve Over() in Apache Pig - hadoop

Question

I'm getting the following error when using Over() in Pig:
Failed to generate logical plan. Nested exception: org.apache.pig.backend.executionengine.ExecException: ERROR 1070: Could not resolve Over using imports: [, java.lang., org.apache.pig.builtin., org.apache.pig.impl.builtin.]
The error occurs upon execution of the closing brace for C:
A = load 'data/watch*.txt' as (id,ts,watch);
B= GROUP A BY id;
C= FOREACH B {
C1 = ORDER A BY ts;
GENERATE FLATTEN(Stitch(C1,Over(C1.watch,'lag',-1,0)));
}
It seems to me that Over() is not included in my Pig but I'm not sure why because I believe my versions of pig and hadoop should be sufficiently up to date.
$ pig -version
Apache Pig version 0.12.1-SNAPSHOT (rexported)
compiled Feb 19 2014, 16:31:42
$ hadoop version
Hadoop 2.2.0
Subversion https://svn.apache.org/repos/asf/hadoop/common -r 1529768
Compiled by hortonmu on 2013-10-07T06:28Z
Compiled with protoc 2.5.0
From source with checksum 79e53ce7994d1628b240f09af91e1af4
This command was run using /usr/local/hadoop/share/hadoop/common/hadoop-common-2.2.0.jar
Any insight would be much appreciated. I'm wondering at this point if I should just use an Over() UDF from PiggyBank.

Answer 1

I believe there is no OVER function in the built-ins for Pig v12. You need to use the OVER function in piggybank.
REGISTER piggybank.jar
DEFINE Over org.apache.pig.piggybank.evaluation.Over();
A = load 'data/watch*.txt' as (id,ts,watch);
B= GROUP A BY id;
C= FOREACH B {
C1 = ORDER A BY ts;
GENERATE FLATTEN(Stitch(C1,Over(C1.watch,'lag',-1,0)));
}