PreLog: A Pre-trained Model for Log Analytics

Large-scale software-intensive systems often produce a large volume of logs to record runtime status and events for troubleshooting purposes. The rich information in log data enables a variety of system management and diagnosis tasks. Over the years, many approaches have been proposed for automated log analytics. However, these approaches usually design separate models for each specific task, which cannot be generalized to other tasks. They are also not robust when dealing with logs from heterogeneous sources. In this paper, we propose PreLog, a novel pre-trained model for log analytics. PreLog is pre-trained on a large amount of unlabelled log data to capture the semantic meaning of logs. We design two log-specific pre-training objectives, including entry-level and sequence-level objectives, which enable PreLog to better understand the hidden structure and semantics of logs. To perform downstream log analytics tasks, we leverage a prompt tuning paradigm to convert downstream tasks' objectives into a similar form as the pre-training stage. We have conducted extensive experiments on two main log analytics tasks (i.e., log parsing and log-based anomaly detection). Experimental results show that PreLog achieves better or comparable results in comparison with the state-of-the-art, task-specific approaches. PreLog is cost-effective and can be uniformly applied to many log analytics tasks through the prompt tuning paradigm.