Partition Projection

Athena partition projection calculates partition values and locations from configured rules instead of retrieving individual registered partitions. It is a metadata-discovery technique, distinct from projection that selects columns.

For example, a date range and location template can generate candidate date paths. Athena then prunes them using the query. Enabling this feature makes Athena ignore registered partition entries for that table; other engines may still depend on those entries.

A projected location need not exist. An absent path returns no data, and a query beyond configured bounds can return zero rows without an error. A successful query therefore does not establish delivery completeness. Check ranges and expected periods independently.

Use this approach when the location pattern is predictable and test its performance with the actual distribution. Many empty combinations can waste work. Projection neither creates files nor marks a writer’s multi-file output complete.

See External Tables and the Lake/Warehouse Boundary for worked examples.

Reference: Official documentation.