What is the difference between Qdrant upsert and separate insert/update operations?

Qdrant's upsert operation writes a point identified by its ID. If the ID does not exist, the point is created; if it already exists, the stored point is replaced or updated according to the upsert request semantics.

This is useful for ingestion pipelines because the same write can be retried without requiring a separate existence check. That reduces race conditions and makes at-least-once event processing easier to implement.

The trade-off is that an upsert can overwrite data you did not intend to replace if the payload or vector in the request is incomplete. When I need to modify only one aspect of an existing point, I use the specific update operation, such as payload update, rather than treating every change as a full replacement.

A common mistake is assuming upsert is automatically transactionally safe across Qdrant and the source database. It provides idempotent point-level write behavior, but cross-system consistency still requires application-level design.