1. A program product for optimizing a parallel data integration job, the program product comprising: a nontransitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising: computer readable code configured to receive a job request specifying a parallel data integration job to deploy in a grid, wherein the job request includes operators specifying parallel integration operations performed when the parallel data integration job is run; computer readable code configured to predict grid resource utilizations for hypothetical runs of the specified job on respective hypothetical grid resource configurations responsive to a model based on performance data from a plurality of actual runs of previously deployed, parallel data jobs; and computer readable code configured to select a grid resource configuration for running the parallel data integration job, including resource optimizer module computer readable code configured to automatically select a grid resource configuration responsive to the predicted grid resource utilizations and an optimization criterion based on at least one resource utilization index for the job; and computer readable code configured to generate the at least one resource utilization index for the job, comprising: computer readable code configured to generate resource utilization indices for each respective operator responsive to the predicted grid resource utilizations on resource portions; computer readable code configured to generate a respective operator index maximum for each respective operator; computer readable code configured to generate, for each of a respective group of the operators, a respective maximum of the operator index maxima among the operators of the respective group; computer readable code configured to select a first maximum of resource utilization indices for a first and second subset of data source and sink operator groups; computer readable code configured to select a second maximum of resource utilization indices for a first and second subset of processing and scratch operator groups; and computer readable code configured to generate the at least one resource utilization index for the job responsive to a ratio of the first and second maxima.