Datasets & retention policies
An explicit time cutoff and optional equality filter define what is eligible.
Selection rule
A policy references a saved source, destination, schema/database, table/collection, time field, retention age and batch size. Selection is strict time < cutoff. SQL connectors also accept one paired text equality predicate; MongoDB does not support equality filters. NULL or missing retention values are not eligible. Arbitrary SQL predicates are not accepted.
Fixed bounds
Each archive fixes a UTC cutoff and upper primary-key bound, then advances by key instead of OFFSET. A later run gets its own bounds and can overlap earlier exports; no incremental watermark or cross-policy deduplication is implemented. Cloud Datasets derives from saved policies rather than a complete database catalog.
Supported export shape
PostgreSQL supports ordinary non-inherited tables with a single smallint/integer/bigint key and up to 1,000 rows per batch. MySQL 8.4 InnoDB supports a single integer key, including unsigned 64-bit keys, and up to 400 rows. MongoDB 8.0 supports ordinary replica-set collections with ObjectId keys, a top-level BSON Date retention field and up to 100 documents. Engine-specific type, topology and byte limits apply; unsupported or oversized records fail without truncation.