Definitions
This document provides definitions for some of TimeBase's key terms.
| Term | Description |
|---|---|
| Class Definition | Describes structure of a message. The className definition lists the fields included in messages of this className, along with their names, data types, limits, and precision. |
| Content Class | A class that describes stream messages. |
| Cursor | API for data consumers. Reading data from one or many TimeBase streams according to the subscriptions. |
| Data Cache | LRU cache in memory for TimeBase data. |
| Inheritance | Message classes can inherit from other message classes. TimeBase supports single inheritance only, just like Java and C#. The inheritance hierarchy forms a tree-like structure. |
| Introspector | API to create class hierarchy from specific Java or C# class definitions. Refer to Introspection to learn more. |
| Live Cursor | Reading data 'live' from one or many TimeBase streams. |
| Loader | API for data producers. Publishes messages into TimeBase streams. |
| Message | A message describes a specific event, and is stored or edited as a unit. Every message in TimeBase is automatically associated with a moment in absolute time and an entity key. The entity is an abstract concept that identifies the object, to which the event relates the most. A message contains a number of data fields according to the message structure. There are two required fields - a symbol (sometimes called key), and a timestamp. |
| Space | Data partition. |
| Stream | A collection of messages ordered by time with a predefined structure. Refer to Streams to learn more. |
| Polymorphic Stream | A stream containing messages of several classes. |
| Fixed Type Stream | A stream containing messages of a single specific class. |
| Durable Stream | The content of durable streams is persisted on disk. |
| Transient Stream | In-memory stream is not persisted anywhere. Messages are stored in a memory buffer, which acts as a queue with one tail and multiple heads. |
| Unique Stream | A stream (Durable or Transient) that supplies a copy of last-known values for each symbol to new stream subscribers. |
| Symbol | A key that describes a specific time-series source (e.g. in IoT it may be a sensor id, or trading activity for a specific security). |
| Term | A high-performance messaging channel that directly connects data Producers and Consumers (via UDP or IPC). |