Sawzall is a procedural domain-specific programming language, used by Google to process large numbers of individual log records.
[2] However, since the MapReduce table aggregators have not been released,[3] the open-sourced runtime is not useful for large-scale data analysis of multiple log files off the shelf.
[4] Google's server logs are stored as large collections of records (Protocol Buffers) that are partitioned over many disks within GFS.
To make it easier to write quick scripts, Rob Pike et al. developed the Sawzall language.
Currently, only the language runtime (which runs a Sawzall script once over a single input) has been open-sourced; the supporting program built on MapReduce has not been released.