1. A database management system comprising: at least one processor and electronic memory; a database-query processor to make multiple calls to a multiple-input, multiple-output-per-input user-defined-function; the multiple-input, multiple-output-per-input user-defined-function to, in response to an invocation: set up a first memory buffer to maintain first input information for a first period equal to a lifetime of the invocation, wherein the first input information is provided to the multiple-input, multiple-output-per-input user-defined-function; set up a second memory buffer to maintain second input information for a second period, wherein the second input information is provided to the multiple-input, multiple-output-per-input user-defined-function; and set up a third memory buffer to maintain output information for a third period, wherein the output information is provided by the multiple-input, multiple-output-per-input user-defined-function.