I am using the Invoice Proposal form from the PSA module and it is horribly slow. My solution had been to add display method caching by calling the cacheAddMethod function on the datasource.
The result is that the form is so slow as to be unusable. Caching two display methods made the form run about 10 times slower than its already dreadful speed.
The form uses numerous joined datasources and the display caching was added to a datasource (ProjProposalEmpl) joined to the main datasource (projProposalJour)
Can anyone tell me why caching is destroying performance?