Improvements relating to handling and processing of massive numbers of processing instructions in real time

A system (150) for processing and handling very high numbers of processing instructions in real time during a processing session is described where each processing instruction specifies resource account data files (30) relating to two different entities (14,16) and the quantity and type of resources to be exchanged between those files (30). The system comprises: a preloader (152) for obtaining reference data relating to the instructions, the reference data indicating the current values of each of the specified resource account data files 30, and the preloader being arranged to read the reference data for a plurality of received instructions in parallel from a master database; an enriched instruction queue (166) for queuing a plurality of the processing instruction together with their respective preloaded reference data; an execution engine (154) arranged to determine sequentially using the received reference data, whether each received instruction can be executed under the present values of the relevant resource account files 30 and for each executable instruction to generate an updating command; and an updater 158, responsive to the updating command from the execution engine (154) for updating the master database (24) with the results of each executable instruction, the operation of the updater being decoupled from the operation of the execution engine.