1. A process for performing computer log analysis, the process comprising: performing an analysis on existing program code that is executable on one or more computers forming part of a distributed computer system, the analysis identifying log output instructions present in the program code, the log output instructions being configured to generate log messages related to service requests processed by the program code; generating a log model using the analysis, the log model being representative of causal relationships among service requests defined by the program code; applying the log model to a plurality of log messages generated by execution of the program code to add log messages of the plurality of log messages into one or more groups; and applying of the log model at a plurality of nodes of the distributed computer system, the plurality of nodes being connected by a network, at least two nodes of the plurality of nodes combining groups of log messages locally without transmitting the log messages over the network before assigning shuffle keys to the groups of log messages and transmitting the groups of log messages over the network to one or more nodes of the plurality of nodes based on the assigned shuffle keys, the one or more nodes further combining received groups of log messages.