问题
I am new to Hadoop/PIG. I have a basic question.
Do we have a Logging facility in PIG UDF? I have written a UDF which I need to verify I need to log certain statements to check the flow. Is there a Logging facility available? If yes where are the Pig logs present?
回答1:
Assuming your UDF extends EvalFunc, you can use the Logger returned from EvalFunc.getLogger(). The log output should be visible in the associated Map / Reduce task that pig executes (if the job executes in more than a single stage then you'll have to pick through them to find the associated log entries).
回答2:
perhaps obvious, but I advise debugging your UDF in local mode before deploying on a cluster/pseudocluster. This way, you can debug it right inside your IDE (eclipse in my case) which is easier than log-debugging.
来源：https://stackoverflow.com/questions/11005004/debugging-in-pig-udf