1. A method for monitoring system performance of an in-memory computer system comprising: executing, by the in-memory computer system, a script written in a SQL query language to perform the steps of: conducting a plurality of on-line transaction processes (OLTPs) to receive and store data in a main memory component of the in-memory computer system; conducting a plurality of on-line analytical processes (OLAPs) on the data stored in the main memory component to produce a plurality of data analysis results; storing the data analysis results in the main memory component; storing runtime information in a plurality of system tables in the main memory component relating to the step of conducting the plurality of OLTPs and the step of conducting the plurality of OLAPs; and performing one or more predetermined data analyses on the runtime information stored in the plurality of system tables in the main memory component to produce a plurality of system performance metrics.