Define a condition naming scheme

[gubser]

An analyzer can observe multiple conditions on a path at the same time. The question is how to name and organise all the different conditions and, almost more importantly, how the value field should look like depending on the condition.

Variant A: one condition per observation

• a result row with N conditions will be transformed into N observations each with identical path, time(, value) etc.
• altough space isn't an issue, there is no benefit in doing so because mongo db's special behavior when operating on arrays. when performing a find-query on an array it looks at every value of the array and returns the document if any item matches the value. ( https://docs.mongodb.com/manual/reference/method/db.collection.find/#query-a-field-that-contains-an-array )

Variant B: each condition combination is a condition

• not really useful if only a string concat and no logic relation to 'basic' conditions.
• results in exploding number of conditions

Variant C: multiple conditions per observation

the field condition is an array: condition: ['cond1', 'cond2', 'cond3']
searching for observations given a single condition is easy because of mongodb's special behavior when operating on arrays. (see link above).

In addition, let's introduce that each condition has defined a mandatory set of keys in the values field. in practice this means for each condition we define a json-schema.

TODO: think about a clever way how to populate the value field associated with multiple conditions without key collisions and too much copies. (mplane registry?)