A completely distributed architecture maintains a single access point. The Metadata retrieval engine responds to user requests by retrieving data from source systems in real time; there is no persistent repository. In this architecture, the Metadata management environment maintains the necessary source system catalogs and lookup information needed to process user queries and searches effectively. A common object request broker or similar middleware protocol accesses these source systems.

Advantages of distributed Metadata Architecture include:

• Metadata is always as current and valid as possible because it is retrieved from its source
• Queries are distributed, possibly improving response and process time
• Metadata requests from proprietary systems are limited to query processing rather than requiring a detailed understanding of proprietary data structures, therefore minimizing the implementation and maintenance effort required
• Development of automated Metadata query processing is likely simpler, requiring minimal manual intervention 
• Batch processing is reduced, with no Metadata replication or synchronization processes

Distributed architectures also have limitations:

• No ability to support user-defined or manually inserted Metadata entries since there is no repository in which to place these additions
• Standardization of presenting Metadata from various systems
• Query capabilities are directly affected by the availability of the participating source systems
• The quality of Metadata depends solely on the participating source systems

This figure illustrates a distributed Metadata Architecture. There is no centralized Metadata repository store and the portal passes the users’ requests to the appropriate tool to execute. As there is no centralized store for the Metadata to be collected from the various tools, every request has to be delegated down to the sources; hence, no capability exist for a global search across the various Metadata sources.