[PIG-125] improve exception handling and expressivness around tuple field access

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.1.0
• Component/s: impl
• Patch Info: Patch Available
• Assignee: Johannes Zillmann
• Reporter: Johannes Zillmann
• Created: 26/Feb/08 22:39
• Updated: 24/Mar/10 22:01
• Resolved: 29/Feb/08 20:40

Description

Stumbled over the case that i'm accessing fields in a tuple which type are not as i expected. The stack trace in one case looked as follow:

Exception in thread "main" java.lang.RuntimeException: execution failed
	at com.my.Executor.run(Executor.java:284)
Caused by: java.io.IOException: Unable to store alias C
	at org.apache.pig.impl.util.WrappedIOException.wrap(WrappedIOException.java:16)
	at org.apache.pig.PigServer.store(PigServer.java:335)
	at org.apache.pig.PigServer.store(PigServer.java:317)
	at com.my.Executor.run(Executor.java:280)
	... 2 more
Caused by: org.apache.pig.backend.executionengine.ExecException
	at org.apache.pig.backend.local.executionengine.LocalExecutionEngine.execute(LocalExecutionEngine.java:137)
	at org.apache.pig.backend.local.executionengine.LocalExecutionEngine.execute(LocalExecutionEngine.java:32)
	at org.apache.pig.PigServer.store(PigServer.java:332)
	... 4 more
Caused by: java.io.IOException: Incompatible type for request getAtomField().
	at org.apache.pig.data.Tuple.getAtomField(Tuple.java:177)
	at com.my.DatabaseStoreFunc.putNext(DatabaseStoreFunc.java:83)
	at org.apache.pig.impl.io.PigFile.store(PigFile.java:64)
	at org.apache.pig.backend.local.executionengine.POStore.getNext(POStore.java:105)
	at org.apache.pig.backend.local.executionengine.LocalExecutionEngine.execute(LocalExecutionEngine.java:130)
	... 6 more

The exception message and the stacktrace gave me a clue what kind of problem i was facing. But to know what exactly happened i needed to debug (or temporarily add some system-outs).
Looking at the code (of Tuple class) i think the exception-information can be improved easily (add index and actual field type information) .
Also it seems that there is some space for simplifying the exception handling.