SPI_execp is the same as
SPI_execute_plan, with the latter's
read_only parameter always taken as
false.
execution plan (returned by SPI_prepare)
An array of actual parameter values. Must have same length as the plan's number of arguments.
An array describing which parameters are null. Must have same length as the plan's number of arguments. n indicates a null value (entry in values will be ignored); a space indicates a nonnull value (entry in values is valid).
If nulls is NULL then
SPI_execp assumes that no parameters are
null.
maximum number of rows to process or return