Starting an OLAP Database

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OLAP Database Overview: Starting an OLAP Database

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The Doradus server is configured as an OLAP database when the following option is used in the doradus.yaml file:

storage_services:
    - com.dell.doradus.service.olap.OLAPService

When the Doradus server starts, this option initializes the OLAPService and places new applications under the control of OLAP storage by default. Details of installing and configuring the Doradus server are covered in the Doradus Administration document, but here’s a review of three ways to start Doradus:

• Console app: The Doradus server can be started as a console app with the command line:

java com.dell.doradus.core.DoradusServer [arguments]

where [arguments] override values in the doradus.yaml file. For example, the argument "-restport 5711" sets the REST API port to 5711.

• Windows service: Doradus can be started as a Windows service by using the procrun package from Apache Commons. See the Doradus Administration document for details.

• Embedded app: Doradus can be embedded in another JVM process. It is started by calling the following method:

  com.dell.doradus.core.DoradusServer.startEmbedded(String[] args, String[] services)

where:

• args is the same arguments parameter passed to main() when started as a console application. For example {"-restport", "5711"} sets the REST port to 5711.

• services is the list of Doradus services to initialize. Each string must be the full package name of a service. The current set of available services is listed below:

  com.dell.doradus.service.db.DBService: Database layer (required)
  com.dell.doradus.service.schema.SchemaService: Schema services (required)
  com.dell.doradus.mbeans.MBeanService: JMX interface
  com.dell.doradus.service.rest.RESTService: REST API
  com.dell.doradus.service.taskmanager.TaskManagerService: Background task execution
  com.dell.doradus.service.spider.SpiderService: Spider storage service
  com.dell.doradus.service.olap.OLAPService: OLAP storage service
  

Required services are automatically included. An embedded application must include at least one storage service. Other services should be included when the corresponding functionality is needed.

If the Doradus server is configured to use multiple storage services, or if OLAP is not the default storage service (the first one listed in doradus.yaml), an application can explicitly choose OLAP in its schema by setting the application-level StorageService option to OLAPService. For example, in JSON:

{"Email": {
   "options": {"StorageService": "OLAPService"},
   ...
}