Inventory must support constrained joins for current device-to-site ownership, while thirty days of poll samples need append-and-window queries. Access patterns fight inside one engine. What is the honest evaluation using only the official database-type families?

When inventory must support constrained joins for current device-to-site ownership while thirty days of poll samples need append-and-window queries, the honest evaluation is to use two fitting official types rather than inventing a sixth hybrid engine. Relational or document storage can hold current inventory with the integrity or flexibility that ownership requires; a time-series store holds the poll samples. Access patterns that fight inside one engine are a signal to split by workload, not to rename two jobs as one magical filing cabinet.

Forcing everything into one graph database because networks always imply graphs ignores that ownership joins and windowed samples are not primarily path-traversal problems. Inventing a new stream-document-columnar engine name as the canonical exam answer invents a type outside the official families the blueprint expects. Storing poll samples only in ChatOps Webex spaces as message attachments is not a database design and cannot support constrained joins or reliable windowed analytics.

Exam caveat: dual-store designs need clear ownership of which system is source of truth for inventory versus samples and a sync or correlation strategy between them. Operational check: prototype device-to-site constrained queries in the inventory store and parallel windowed poll queries in the time-series store for the same device IDs, then confirm operators can join results by a shared device key without a fictional hybrid engine.