Remove repetitive file writes
While inside a loop (for example, from a SQL read or IOS query) it is common for designers to place a File Access node in the process to write out each record from the query to a file. Disk input/output (I/O) negatively impacts performance, so when possible, remove these repetitive file writes with a Message Builder node inside the loop. By doing so, you will be appending all your records to a String in memory which is much faster than writing it out to disk. At the end of the loop, place one File Access node in your process that writes all of the Message Builder node output to a file at once.