SQL Server TEMPDB FULL

Got a new assignment to research why TEMPDB of a SQL Server 2008 64-bit is termination active user and application sessions.

DBA resource suspects a 120 table join is causing the TEMPDB to run out of disk space causing sessions  terminating unexpectedly.

Logged in the database for the first time, reviewed the procedure and tables and views involved. About 10 tables with significantly varying record counts which are joined by PK and other columns. Also the procedure runs in parallel (24 CPU's on the host machine).

Need to figure out the 120 table join, how why and where....

This is going to be a good learning opportunity.

Hopefully we will be able to resolve this TEMPDB issue and some good experience.

Update: Still no update, the users did not want the job running anymore so had to divert my attention towards other tasks.

One thing i suspect is there are 24 CPU's in that server and the job joins 2 tables, 2 views (3 tables in each view AFAIK). Can this be the reason for all those threads running in parallel? MAXDOP is not specified so may be?