systemDb-SystemDbService

The SystemDbService in the Supervisor station is a generic service used to provide access to the System Database for entity data storage and the ability to query for data persisted in the database.

The database is “pluggable”. The default selection is the InactiveSystemDb. Currently, only the OrientDb selection is available.

In Niagara 4.7 and later, OrientIndex configuration components are exposed in the orientSystemDb-se module palette and allow you to manually drag and drop them under a container under the OrientSystemDb component in a running or offline station. When enabled, the OrientIndex components create orient indexes based on the configured settings and are mainly used to improve query performance for commonly queried tags. When disabled or removed, the corresponding orient index is dropped from the underlying Orient database.

The System Database stores entities, tags, and relations indexed from the Supervisor’s local station, or from subordinate stations in its NiagaraNetwork. NEQL is able to query against the System Database. This allows Niagara Search and Hierarchies to query against it.

Properties

In addition to standard properties (e.g. Status, Enabled, Fault Cause, Alarm Source Info, and Monitor, etc.), this component provides the following configuration properties.

Type	Value	Description
System Database Type Selection	InactiveSystemDb (default), OrientDb	Indicates the type of backend database to be used. When initially installed, the default selection is “InactiveSystemDb”. This default inactive selection is intentional because when OrientDb is selected it creates a lot of files in the station protected home directory. So this default inactive selection prevents that from happening if the SystemDbService is accidentally dropped into a station.
System Database	additional properties	See following section.

System Database

Niagara 4.10 and later supports Orient database Encryption. By default database encryption is Enabled. When converting from Orient V2 (4.9 and earlier) to Orient V3 (in 4.10 and later), the Encryption property may degrade query processing performance. This performance degradation may or may not be noticeable. To improve query performance, you can change the Encryption state to Disabled.

To change the encryption state, right click System Database > Actions > Change Database Encryption.

NOTE: Changing the encryption state clears the database. To repopulate the database you need to re-index the system.

Figure 3. System Database property sheet

Type	Value	Description
System Database	read-only	Shows selected systemDb.
Orient Db Server Config File	`module://orientSystemDb/rc/orientdb-server-config.xml`	Read-only field, shows the name of the backend server configuration file.
Database Encryption	`Encrypted` (default) or `Unencrypted`	Read-only field, indicates current Encryption state.

Actions list

Five Actions are available on System Databse.

Start Database
Use Start Database Action Menu to manually start the backend System Databse process, when the System Databse is not running. This action automatically pop up when the parent SystemDbService Starts. So no need to invoke it manually. It is useful when debugging in conjunction with the Stop Databse Action.
Stop Database
Manually stops the backend System Databse process. This action automatically pop up when the parent SystemDbService Starts. So no need to invoke it manually. It is useful when debugging in conjunction with the Start Database Action.
Delete Station Record
Manually deletes entries that are previously indexed into the System Databse for particular NiagaraStations. Normally system indexing updates the System Databse, but if a NiagaraStation is manually removed from the NiagaraNetwork or NiagaraStation is renamed then use this Action to manually remove old System Databse entries.
Delete All Records
Deletes all entries from the System Databse. It clears and restart the System Databse. You need to wait for the next scheduled System Index operation or manually invoke it to repopulate the System Databse entries after invoking this Action.
Change Database Encryption
In Niagara 4.10 and later, in cases where query performance may be noticeably degraded you can change the encryption state to Disabled to improve performance.