Source Files

TelemetryIn refersXINA data models, source files refer to the rawinput data files for mnemonic data (and potentially instants/intervals). These come in atwo flavors, buffer source files and archive source files. Archive files are considered the definitive record of source data model.for a single origin (see below). Buffer source files are an optional feature for less structured data inputs. Scheduled asynchronous tasks merge buffer files for each origin into archive files, allowing the buffer files to be deleted.

Data SourceOrigin

Abstractly, a data sourceorigin (or simply sourceorigin) is a single point of data import to a model. In many cases, a model will only have a single data source;origin; for example, if all data is provided directly from a single instrument, or multiple components are merged into a single data stream through FEDS before import into XINA. In these cases delineation by data sourceorigin is not required in model organzation, and should use this pattern:

In a model group, the data group will be used as the default location for telemetry which does not specify a source.

However, in environments with multiple import points running in parallel, databases must be designed with multiple sources.

In this example each telemetrysource file would need to specify either source_aorigin_a or source_borigin_b. Additionally, each sourceorigin has distinct databases for instant, interval, and mnemonic data. This would be required if each data source provided all three data types. As requirements for instants and intervals are less stringent than mnemonics, in some circumstances instants and intervals could be considered a single source and populated independently:

TelemetryBuffer Database

Each model must contain a single telemetrybuffer source file database.

Required Fields

Field	Type	Description
srcorg	asciivstring(32) (may be null)	data sourceorigin name
u_id	uuid	universally unique ID
name	utf8vstring(128)	file name
t_start	instant(us)	start time of telemetrydata datain file
t_end	instant(us)	end time of telemetrydata datain file
meta	jsonobject (may be null)	arbitrary metadata as needed
format	asciivstring(16)	file format (see below)
conf	jsonobject (may be null)	configuration parameters, depending on format

If srcorg is null, the telemetry file will be associated with the default source (and data) group.

TelemetryArchive Database

Each model must contain a single archive source file database. It may either be configured as a single file per record or multi-file per record structure.

Required Fields

Field	Type	Description
org	asciivstring(32) (may be null)	origin name
u_id	uuid	universally unique ID
name	utf8vstring(128)	file name
t_start	instant(us)	start time of data in file
t_end	instant(us)	end time of data in file
meta	jsonobject (may be null)	arbitrary metadata as needed
format	asciivstring(16)	file format (see below)
conf	jsonobject (may be null)	configuration parameters, depending on format

If org is null, the telemetry file will be associated with the default source (and data) group.

Source File Formats

Currently there is only one natively supported general purpose format, using the code csv/tsv. The full documentation is available here. Additional formats will be added in the future, and custom project specific formats may be added as needed.

Assumptions and Limitations

Each telemetry file is considered the single source of truth for all mnemonics, instants, and intervals for it's associated data source for its time range. This has the following implications:

Telemetry files with the same source cannot contain overlapping time ranges. If an import operation is performed with a file violating this constraint the operation will fail and return an error.

Within a single model, each mnemonic may only come from a single source. Because mnemonics are not necessarily strictly associated with models, and the source may vary between models, this cannot be verified on import and must be verified on the client prior to importing data.

Data Flow

Telemetry data flow involves two phases, the import phase and the mining phase. Telemetry files must be imported with the MODEL_TM_IMPORT action. Files are parsed with some degree of validation (details depend on file format) and imported into the model telemetry database. Once this is complete the mining phase begins. This is performed asynchronously as a XINA Run task. Mining tasks are executed sequentially for each model by specifying a XINA Run thread for the model.

Full details of the mining process vary depending on the file format. The default csv format mining tool is documented here.

All of these concepts merge together into two core paradigms of data flow management: server side aggregation, and client side aggregation.

Server Side Aggregation

With server side aggregation, the XINA server is responsible for aggregating one or more data services into a model. Typically this means XINA is also responsible for management of mnemonic definitions, using the MODEL_MN_IMPORT API call.

Pros

• minimal client side configuration required to get started
• flexible and responsive to changing environments, mnemonics, requirements

Cons

• performance is worse than client side aggregation
• not recommended above 1k total data points per second
• less stringent validation means user mistakes may go unnoticed

Client Side Aggregation

With client side aggregation, data for a model is entire aggregated into a single data source on the client. This solution is common for telemetry generated directly by an instrument, or multiple sources merged through FEDS. Typically the merged file(s) are a binary format and require custom utilities to convert to XINA formats, which can be deployed within the XINA ecosystem to XINA Run servers.

Pros

• much higher performance ceiling than server side aggregation
• stringent validation ensures data conforms to standard

Cons

• more complex initial setup
• mnemonic definitions need coordination between client and server
• changes are more complex and likely involve human interaction