Precompress

Precompress is the practice of applying data compression before data is transmitted, stored, or further processed, with the goal of reducing bandwidth usage and storage requirements. It complements, but is not identical to, on-the-fly or post hoc compression.

It is commonly used in content delivery pipelines, build and packaging systems, and data backup or archival workflows. In such contexts, precompression can be performed as a prebuild step, a scheduled batch job, or as part of an automated data workflow.

Techniques include selecting an appropriate compression algorithm and level, choosing file-level versus block-level compression, and applying domain-specific preprocessing such as metadata removal, deduplication, or tokenization to improve compression ratios.

Benefits include lower network transfer times, reduced storage costs, and potential throughput gains when distributing large data sets. Drawbacks can include longer preparation times, increased CPU usage, possible incompatibilities with decompression tools, and diminishing returns on data that is already compressed.

Key considerations are data mutability, reproducibility of the precompression, and the need to recompress when data changes. It is important to store sufficient metadata to enable decompression and to ensure that the precompressed artifacts remain accessible to clients and systems that rely on them.

Related concepts include general compression, data deduplication, archival packaging, and content delivery networks. Precompression is often contrasted with live compression performed at the time of transfer.