Application of consistency level during collection creation versus query/search time

[deepns]

If I create a collection with some consistency level (say default level of Bounded Staleness or something else), can the consistency level be overridden with a higher or lower consistency level during a query/search operation? Is there any restriction that consistency level specified in the query/search has to be same or lesser than what is specified during collection creation?

[yhmo]

Sure, consistency level can be overridden by query/search.

# the collection is created with consistency_level
client.create_collection(collection_name, dim=512, consistency_level="Bounded")

# you can change to any level for query/search, no restriction
client.search(collection_name=collection_name, consistency_level="Strong")
client.search(collection_name=collection_name, consistency_level="Eventually")

[deepns]

Thanks. Are the timestamps mentioned in unit of seconds?

For e..g https://github.com/milvus-io/milvus-sdk-go/blob/master/client/meta_cache.go#L9C1-L14C2

// Magical timestamps for communicating with server
const (
	StrongTimestamp     uint64 = 0
	EventuallyTimestamp uint64 = 1
	BoundedTimestamp    uint64 = 2
)

Depending on the consistency level provided to the search/query request, GuaranteeT is set to one of the above.

[xiaofan-luan]

Thanks. Are the timestamps mentioned in unit of seconds?

For e..g https://github.com/milvus-io/milvus-sdk-go/blob/master/client/meta_cache.go#L9C1-L14C2

// Magical timestamps for communicating with server
const (
	StrongTimestamp     uint64 = 0
	EventuallyTimestamp uint64 = 1
	BoundedTimestamp    uint64 = 2
)

Depending on the consistency level provided to the search/query request, GuaranteeT is set to one of the above.

Those a re enum numbers.

Strong means you always get what you write.
Evetually means you get what you write eventually but there is no gurantee.
BoundedTimestamp means you can specify a time to delay, by default it's a 1 minutes but it's tunable

[deepns]

How we do tune up the time-to-delay for Bounded consistency level? Is gracefulTimeout the parameter to use for that?

Looking at this config, https://milvus.io/docs/configure_common.md#commongracefulTime - gracefulTimeout is set to 5 seconds.
https://milvus.io/docs/timestamp.md#Gracefultime

Where is the time-to-delay set to 1 minute for Bounded consistency?