CollectionParamsDiff
The parts of a collection's configuration that can be changed after it exists.
Several of these could only be chosen at creation before, which mattered most for the newest one: memory tiers arrived in Qdrant 1.19 and payloadMemory set a collection's payload placement at creation, so moving an existing collection from cold to cached, which is the whole point of a tier, meant recreating the collection. The replication factor is the same story for a cluster that grew.
A field left null is left unchanged, which is the opposite of how QuotaConfig behaves and is worth knowing before using either.
vectors and sparseVectors are on Qdrant's own update request and deliberately not here: they change what the collection stores rather than how it is placed, and they belong with the vector-config work rather than with this.
Properties
Deprecated by Qdrant 1.19 in favour of payload.
Payload placement. Overrides onDiskPayload when both are set.
How long to wait before trying another replica, in milliseconds.
Extra remote nodes every read is also sent to, answering with the first response back.
Replicas the cluster tries to maintain for each shard.
Replicas that have to acknowledge a write for it to count.