Revision 1221830

HIVE-2666 [jira] StackOverflowError when using custom UDF in map join
(Kevin Wilfong via Yongqiang He)

Summary:
Resource files are now added to the class path as soon as they are added via the
CLI.  This fixes the stack overflow error mentioned in the JIRA by ensuring a
consistent class loader between serializers and deserializers for the same
query.

Note that now serdes which contain a static block to register themselves are now
registered twice, once when adding the file to the class loader, and once when
an instance of the class is created.  Previously, registering a serde twice
resulted in an exception, to avoid this, I have downgraded it to a warning.

When a custom UDF is used as part of a join which is converted to a map join,
the XMLEncoder enters an infinite loop when serializing the map reduce task for
the second time, as part of sending it to be executed.  This results in a stack
overflow error.

Test Plan:
I ran the unit tests to verify nothing was broken.

I ran several queries which used custom UDFs and involved a join which was
converted to a map join.  I verified these completed successfully consistently

Reviewers: JIRA, heyongqiang

Reviewed By: heyongqiang

CC: heyongqiang, kevinwilfong

Differential Revision: 957