Source Files
In XINA data models, source files refer to the input data files for mnemonic data (and potentially events). These come in two flavors, buffer source files and archive source files. Archive files are considered the definitive record of source data 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.
Origin
Abstractly, a data origin (or simply origin) is a single point of data import to a model. In many cases, a model will only have a single data 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 origin is not required in model organzation, and should use this pattern:
However, in environments with multiple import points running in parallel, databases must be designed with multiple origins.
In this example each source file would need to specify either origin_a or origin_b. Additionally, each origin 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:
Buffer Database
Each model must contain a single buffer source file database. It is configured as single-file-per-record.
Required Fields
| Field | Type | Description |
|---|---|---|
origin |
asciivstring(32) |
origin name |
uuid |
uuid |
universally unique ID |
name |
utf8vstring(128) |
file name |
t_min |
instant(us) |
earliest time of data in file |
t_max |
instant(us) |
latest time of data in file |
format |
asciivstring(16) |
file format (see below) |
conf |
jsonobject (may be null) |
configuration parameters, depending on format |
Archive Database
Each model must contain a single archive source file database. It is configured as a multiple-file-per-record structure.
Required Fields
| Field | Type | Description |
|---|---|---|
origin |
asciivstring(32) |
origin name |
uuid |
uuid |
universally unique ID |
p_id |
int(8) |
primary ID |
s_id |
int(4) |
secondary ID |
t_start |
instant(us) |
start time of data in file |
t_end |
instant(us) |
end time of data in file |
duration |
duration |
t_end - t_start |
t_min |
instant(us) |
earliest time of data in file |
t_max |
instant(us) |
latest time of data in file |
label |
utf8vstring(128) |
plain text label |
content |
utf8text |
extended text / CSV / HTML |
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 |
type |
int(2) |
interval type code |
level |
int(1) |
level code |
Source File Formats
Currently there are two natively supported general purpose formats, one using the codes csv/tsv (full documentation here), and a binary format using the code xbin (full documentation here) Additional formats will be added in the future, and custom project specific formats may be added as needed.
Data Flow
XINA model data input involves two phases, the import phase and the mining phase. The approach to these phases differs depending on whether data is being imported with buffer files or archive files.
Buffer Import
Buffer files are imported with the MODEL_BUFF_IMPORT action. This invokes three effects:
- the raw buffer file is parsed, validated, and stored in the model source buffer database
- new definitions are created for any unrecognized mnemonic labels
- data is added to the mnemonic buffer database for the associated origin
No additional data processing occurs as part of this step. XINA models utilizing buffer source files must implement routine execution of the MODEL_BUFF_ARCH asynchronous task (typically every 24 hours) to merge the files into archive files, which can then be processed by MODEL_ARCH_MINE tasks to fully process data into model standard databases.
Pros
- minimal client side configuration required to get started
- allows smaller, faster file uploads to view data close to real-time
- 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
Archive Import
Alternatively, archive files may be imported directly with the MODEL_ARCH_IMPORT action.
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
Assumptions and Limitations
Each archive source file is considered the single source of truth for all mnemonics, instants, and intervals for it's associated origin for its time range. This has the following implications:
Archive files with the same origin 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 origin. 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.