DataMerge to a pdf not in memory InDesign(cc2014) JavaScript

Question

I am having an issue with the file merging in ram not to a pdf document.
When I am merging 20 thousand records having it merge in ram not only takes for ever it some times runs out of ram.
any ideas? This is my Current code.
              var jobNumber = prompt("what is your job number");
             // Setting the Folder to get the indesign and the Data File file from.
            var myTemplateFolder = Folder("~/Documents/hotfolder/template/");
            var myDataFolder = Folder ("~/Documents/hotfolder/data/");
            // Retrieving the Indesign FIle
            var myTemplates = myTemplateFolder.getFiles("*.indd");
            var myDataSet = myDataFolder.getFiles("*.csv");
            //Open the Template and Declare its value of myDocument
            var myDocument = app.open(File( myTemplates ));
            // Turning on the BackGround Layer For Proofing
            var myLayer = app.documents.item(0).layers.item("Background");
            myLayer.visible = false ;
            //Setting the data source to be merged    
            myDocument.dataMergeProperties.selectDataSource(File(myDataSet));
            // Merging the Records and creating the overset text document to make sure nothing is wrong with the file.     
            myDocument.dataMergeProperties.mergeRecords(File("~/Documents/hotfolder/output/"+ jobNumber+"-composedoverset.txt"));
            //close the unmerged document.     
            myDocument.close(SaveOptions.no);
            //Exporting the merged document as composed file
            app.activeDocument.exportFile(ExportFormat.pdfType, File("~/Documents/hotfolder/output/"+ jobNumber+"-composed.pdf"),false,"bandwPrinting");
            //Closing the merged document.
            app.activeDocument.close(SaveOptions.no);
            alert("Complete");

Answer 1

I am sorry I did not ask the question properly.
The attached code does work on my system The template has the place holders already set. (We use this template already to produce about 100 thousand records a day with another system)
the .csv is routed through another routine before it is put in that folder to get rid of any bad characters. It also maps the headers to the placeholders.
The output folder is on my system
the preset is a preset on my system.
What I am asking is how do I produce Directly to a pdf not into memory.
When I try to produce 25 -35 thousand records it fills the memory and gets stuck.
Several plugins do not have this problem I am relatively certain that they are not merging directly into InDesign but into a pdf.