I have a simple transformation that reads the rows to be deleted from a PostgreSQL database, and then delete them from MSSQL. I am only getting about 8 rows a second on the delete step. Does anyone have an idea of how I can speed this up?

Things I have tried:
1. using the primary key field of the table (so it is indexed)
2. modifying commit size: a commit size of 5 gave me 6 rec/sec, while a commit size of 500 only gives me 8. Not much change here.

I am using the JTDS-1.3.1 driver, and PDI 5.3, Centos 7.0 x64, java 1.7