Logical Source

Logical Source represents the logical collection of physical data sources sharing common properties. For example, in a smart city scenario “Street Lamps” are collectively a logical source. However, there could be thousands of physical street lamps within a city. NES uses the concept of Logical Sources to group data sources that share common physical characteristics and data schemas into one larger data source.

A Logical Source contains the source name and the schema information. Any Physical Source that wants to register as part of the Logical Source should have the same schema. Otherwise it will result in a query execution failure.

Physical Source

Physical Source represents the physical data source that belongs to a logical source. In the previous example of the logical source “Street Lamps”, a physical source could be “Street Lamp 1” at some physical location within a city. For one logical source, there could be multiple Physical Sources.

NES manages Physical Sources centrally at the coordinator in a catalog. When a worker with a data source starts, it passes the information about the name of a logical source, the worker information, and other configurations to the coordinator for registration. If the Logical Source used for the registration does not already exist at the coordinator, then the registration will result in a failure.

 
logical_physical_stream.txt · Last modified: 2022/02/23 07:21 by 134.96.191.189
 
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