How do I debug an ETL process that is unable to commit any records?

I used a DB link to connect to another DB and delete a couple of records. Later I ran an Informatica Workflow (ETL tool) to load data into that database using a DB connection that connects directly to it. The Workflow hasn't committed any records since 2hrs (it should run just for 30mins or so..) so I am guessing it is because I was not able to run "commit" using the DB link. *The ETL tools logs don't provide any error or debug information at this point.* Any ideas how I could debug this..? I ran another ETL process to update a table and then run commit. But even after that the first process keeps on running without committing any records. I am not a DBA expert so probably am misinterpreting the DB behavior.. would really appreciate any suggestions. Thanks!