Zero Copy Explained: How ServiceNow Queries Live Data Without Duplication

Zero Copy is a data-access technique that allows systems to query and temporarily use external data without physically duplicating it, eliminating the need for traditional ETL pipelines. ServiceNow applies this through Virtual Data Fabric Tables, which fetch data on demand, hold it briefly in memory, and discard it once the user is done. The approach reduces storage overhead, removes the need for data syncing, and simplifies security management on the destination system. However, Zero Copy comes with notable trade-offs, including full dependency on source system uptime, potential latency issues, increased load on the source, and higher API costs from frequent live queries. Experts recommend using Zero Copy selectively, particularly when the risks and costs of duplicating data outweigh the drawbacks of live querying.