Glossary

Glossary

Definitions of the terms used across this documentation. Each term is defined once here; other pages link back to it.

Audience: all readers.

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API gateway - The deployment's REST control surface. It aggregates every component in a deployment so that a single request can read state or statistics from across the system. It is addressed by the convention name mf-api-gateway. See Operations: Monitoring & Diagnostics.

Composition - A Docker Compose recipe that wires a set of Elastic MDS images together into a running deployment - for example, the Docker Compose file behind the Demo cookbook entry, the one the Quick Start uses. Compositions are worked templates for the deployment topologies: ideal for development, evaluation, and single-host lab or on-premises use, and a starting point you adapt. A conventional install needs no composition at all, and production at scale runs the same service catalog on Kubernetes. See Deployment: Basics and Deployment: Advanced.

Content - The data Elastic MDS delivers to applications, whether real-time (continuously updating) or static. Content is represented as tables of fields; each unit of content is identified so that an application can request it and the platform can locate and deliver it.

Content adapter - A component that understands a particular kind of data source - a market-data feed, a relational database, a set of files - and represents that source's data as Elastic MDS content. Each source type has its own adapter; the rest of the system works against content uniformly.

Content table - The representation of content as a set of fields with identified rows. Applications read content tables with SQL or subscribe to them by topic.

Context - The named context an application selects (the -context value, or the ContextName property), which determines the topic-naming convention. Applications written for MetaFluent v5 use com.metafluent.jms_context.mds and get the v5 feed.symbol grammar, unchanged; MarketData-6.0.0 is an explicit opt-in for generic, schema-qualified addressing. See JMS Application Development.

Deployment project - A repository that packages the configuration and the start / stop scripts for running one Elastic MDS image - for example, deploy-mf-mds-consolidated. Each deployment project pairs with a corresponding image; the Image Catalog lists them. See Deployment: Basics.

Distribution - How requested content reaches an application over the wire. Elastic MDS delivers content by push or by refresh (see those entries). See Architecture: Advanced.

Elastic MDS - MetaFluent's Market Data System: an enterprise platform that gives applications unified, standards-based access to real-time and non-real-time content. It is built on the StreamLens framework.

Entitlement - A rule that controls which content an application or user may access. Elastic MDS enforces the entitlements of the underlying data sources, at the row and field level where required. See Access Control.

Image - In push distribution, the initial snapshot of a content item's current field values, delivered when an application first subscribes, ahead of any updates. See JMS Application Development.

Interest-driven - The principle that content is ingested and kept current only while an application is interested in it; when no application is interested, the resources holding it can be released.

Projector - A deployable unit that hosts one or more content adapters. A deployment runs one or more projectors, each responsible for some set of content.

Push - A distribution mode in which each change to a content item is sent to the subscribing application as it happens. See Architecture: Advanced.

Query - How an application states the content it wants, using SQL or a topic subscription. An application does not need to know which adapter or host holds the data.

Refresh - A distribution mode in which the application reads the current values of content when it needs them, rather than receiving every change. See Architecture: Advanced.

Session - An application's authenticated connection to Elastic MDS, together with the context under which it accesses content.

Simulator - A component that replays recorded market data as a stream, used to supply content for evaluation without connecting a real data source - the mf-eta-simulator in the Quick Start.

StreamLens - The integration framework that Elastic MDS is built on. It provides the platform services - session management, content orchestration, distribution, and monitoring - that content services use.

Topic - The name by which an application subscribes to a unit of content over JMS. How a topic name is interpreted depends on the context in effect (see Context).

Update - In push distribution, a message carrying a change to a content item's field values, delivered after the initial image. See JMS Application Development.