I work with Pentaho data integration a fair amount at work. When I try to run jobs locally the insert speed is ridiculously slow. I found this article that gives a good way to speed up the inserts.
TLDR: add useServerPrepStmts=false, rewriteBatchedStatements=true and useCompression=true to database connection options and things speed up quite a bit on the insert side. I still need to find a way to may insert/update faster.