Hi Alan,

Thanks for the detailed comments.

1. I incorporated your comment. All error messages will have an error

2. Its already mentioned in the section on Error Handling.

3. I have an example for the semantic error. Will add a runtime Hadoop

4. Hadoop error will have different information indicating Hadoop as the

5. I have added some examples to explain this point.

6. Only aggregation will be turned off. Probably we might want to add a
switch to turn off warnings completely.


-----Original Message-----
From: Alan Gates [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, October 21, 2008 11:48 AM
Subject: Re: Requirements for Pig Error Handling


1) "Error codes will be devised for common error messages".  All  
errors should have codes.  We will probably need a catch all category  
(like "internal error" or something).  Giving all error messages  
codes makes it much easier to write user manuals.

2) I think you are assuming that the stack traces etc. that is  
currently output will be written to a log, but I don't see that spell  
out.  You mention that users are responsible for purging it.  You  
also need to specify where the log will be located.

3) A few explicit examples of how things will look would be helpful.  
For example, if you showed a semantic error and a runtime hadoop  
error, what was printed to the screen in each case, and what was  
written to the log in each case.

4) How will errors from hadoop be shown differently than errors from  
pig?  Do you mean they'll have a different error code?  Will they  
contain different information?  Will they be written to different  

5) What does warning aggregation look like?  Will the user get  
something like:  "This query had 500 warnings, see logs for details"  
or will it be "The warning "divide by 0" was seen 498 times and the  
warning "my udf flopped" was seen 2 times" (that is summary of all  
warnings or summary by warning type)?  Will the full warning info be  
written to the logs, or only the summary?

6)  When users turn off warning aggregation, does that mean that the  
warnings are thrown away or that they are printed to the screen  
individually?  That is, does it turn off warnings or turn off  


On Oct 20, 2008, at 3:29 PM, Santhosh Srinivasan wrote: