Databases. A server can host multiple databases
Identified by sequential numbers starting from zero
Each database is a key value store
Keys are binary safe strings
Keys can have expiration time
Values are typed
Value Types. Binary safe string
Can also be interpreted as an integer or a float or a bitmap
List
Ordered list of binary safe strings
Atomic element removal from both ends
Set
Set and sorted set of binary safe strings
Sorted set keeps float score with each element
Hash
A key value map of binary safe strings
Stream
A stream of key value maps of binary safe strings
Individual consumers query entries by timestamp
Consumer groups can cooperate in processing
Hyper Log Log estimator
Opaque type for estimating set cardinality