Create the Historian snapshotter

[marl0rd]

Historian is a important feature in Eru and it have a pretty basic concept:

The Historian is a thread that takes snapshots of the tags each fixed time and save it in the Historic table in the database.

There is some details about functionality:

1. Only the Historian Enabled tags are taken into consideration to be included in historic table.
2. The historian has to run in a isolated thread.
3. The sampling time is fixed and configured in the preferences.
4. The Historian thread start running when the SCADA is launched.
5. Each time the Historian is started, new columns have to be added to the table if a new tag is created and historian enabled. If a tag is no more historian enabled, the column in the historian table have to be deleted.

[marl0rd]

This is an example of what historic table looks like with 3 tags:

[gilbertojrequena]

Are DISTANCE, SPEED and FUEL tags?

[marl0rd]

Yes. Read from a car computer.

[marl0rd]

But, if you guys implement the Jason array technique, would be a 2 columns table...