Events
To organize time based data in XINA, we employ events, which come in two forms: instants, referring to a single moment in time, and intervals, referring to a range of time. The goal events is to make it easy to find, compare, and trend data. Each has their own databases and include fields for:
- type indicate how the event should be viewed and interpretted
- UUID (universally unique identifier, generated at the creation of the event)
- numeric primary and secondary IDs (meaning can depend on subtype)
- plain text label (up to 128 bytes)
- plain text or HTML content
- optional JSON object metadata
Why all these IDs? The UUID uniquely identifies an event, and is the only way to permanently, globally specify it. It should be applied at the time of creation to ensure consistency even if data is reprocessed. The primary / secondary IDs are optional, and can be used as needed. The general idea is that its much faster and more reliable to query numbers than text, so this is the best way to indicate events having commmon meaning.
Instants
Instants provide a reference to a single moment in time. They are not intended to imply any duration.
Instant Database
Default Location
<model>.data.ins
<model>.data.insf (single file per instant)
<model>.data.insfs (multi file per instant)
Required Fields
| field | type | description |
|---|---|---|
uuid |
uuid |
UUID |
p_id |
int(8) |
primary ID |
s_id |
int(8) |
secondary ID |
t |
instant(us) |
time |
type |
int(2) |
instant type code |
level |
int(1) |
level code |
label |
utf8vstring(128) |
plain text label |
content |
utf8text |
extended text / CSV / HTML |
meta |
jsonobject |
additional metadata as needed |
conf |
jsonobject |
additional information specific to type |
Standard Types
| type | code | description |
|---|---|---|
message |
0 |
Basic instant, recommended to use standard IDs to indicate common events |
alert |
1 |
Higher priority variant of message |
2D dataset (DSV) |
1000 |
General purpose 2D data set (see below) |
Intervals
Intervals provide a reference to a span of time, specified by a start time and an end time.
Interval Database
Default Location
<model>.data.int
<model>.data.intf (single file per interval)
<model>.data.intfs (multi file per interval)
Required Fields
| field | type | description |
|---|---|---|
uuid |
uuid |
UUID |
pid |
int(8) |
primary ID |
sid |
int(4) |
secondary ID |
t_start |
instant(us) |
start time (inclusive) |
t_end |
instant(us) |
end time (exclusive) |
d |
duration(us) |
t_end - t_start |
int |
boolean |
true if event is an interval, false if event is an instant |
open |
|
true if event is an open interval, false otherwise |
type |
int(2) |
interval type code |
level |
int(1) |
level code |
label |
utf8vstring(128) |
plain text label |
content |
utf8text |
extended text / CSV / HTML |
meta |
jsonobject |
additional metadata as needed |
conf |
jsonobject |
additional information specific to type |
Standard Types
| type | code | description |
|---|---|---|
marker |
100 |
Basic interval, recommended to use standard IDs to indicate common events |
test |
101 |
TODO |
2D dataset (DSV) |
1000 |
General purpose 2D data set (see below) |
2D Dataset Format
The event standard type 100 indicates a 2D data set. This is typically used with the single file per event database structure, in which case the file will contain the data set. For event databases without files, the data is stored in the content field. This is only recommended for small datasets (less than 1MB).
Files must be either ASCII or UTF-8 encoded. New lines will be interpretted from either \n or \r\n. The conf object may define other customization of the format:
Conf Definition
| Key | Value | Default | Description |
|---|---|---|---|
delimiter |
string |
auto detect (',', '\t', ';') |
value delimiter |
quoteChar |
character |
" (double quote character) |
value quote character |
ignoreLines |
number |
0 |
number of lines to skip before the header |
invalid |
null, 'NaN', number |
null |
preferred interpretation of invalid literal |
nan |
null, 'NaN', number |
null |
preferred interpretation of 'Nan' literal |
pInfinity |
null, 'Inf', number |
null |
preferred interpretation of positive 'Infinity' literal |
nInfinity |
null, 'Inf', number |
null |
preferred interpretation of negative 'Infinity' literal |
utc |
boolean |
false |
if true, interpret all unzoned timestamps as UTC |
Starting after the number provided for ignoreLines, the content must include a header for each column, with a name and optional unit in parentheses. Special standard unit names may be used to indicate time types, which will apply different processing to the column:
| Unit | Description |
|---|---|
ts |
text timestamp, interpretted in local browser timezone (absent explicit zone) |
ts_utc |
text timestamp, interpretted as UTC timezone (absent explicit zone) |
unix_s |
Unix time in seconds |
unix_ms |
Unix time in milliseconds |
unix_us |
Unix time in microseconds |