I am trying to join two fairly large tables (table 1: 3.6 million rows, 112 columns; table 2: 580k rows, 50 columns) and my joins go very quickly until 52% and they don't progress beyond that. I have tried letting it run overnight, but the problem persists. The funny thing is, until a few days ago I frequently performed joins on tables this large or larger with no issue. I doubt my laptop is the problem, as I am running 32 GB RAM with 8 Intel i7 processors and a 1TB SSD drive.
I have already imputed missing values (as I know these can slow down joins in KNIME). I have also cut down the table size by using a reference row filter prior to the join, which usually works like a charm, but is not working in this case.