Remote troubleshooting session connection?

I'm working on an ETL system that is driven from Java/JDBC but is implemented mostly as SQL queries against a
PostgreSQLdatabase.   

An ETL "job" runs inside its own transaction and consists of a series of queries that transform the data from staging
tablesto the destination tables.  If a failure occurs, the transaction rolls back so there's no "debris" left over --
whichmakes troubleshooting very difficult.   

In the Java world we have JPDA, which allows us to connect to a running JVM to examine the state of variables and set
breakpoints,etc. 

Assuming I can pause the driving Java code between queries in a job, is there any way to connect from PGAdmin (or
anothertool) and view the state of tables in the in-progress transaction?  If this is not currently possible, how
difficultwould it be to do?