Sharing Analytic Workspaces

Sharing analytic workspaces across sessions

An analytic workspace can be accessed simultaneously by several sessions. However, only one session can have the analytic workspace open with read/write access at any given time.

When you attach an analytic workspace, your default access to it is read-only. OLAP Services supports simultaneous access for one writer and many readers of an analytic workspace. Provided your user ID has the appropriate access rights, you can always get read-only access to an analytic workspace, no matter how many other users are using it. If another user has read/write access and updates the analytic workspace, then your view of the analytic workspace does not change; you must detach and reattach the analytic workspace to see the changes.

If you want read/write access, then you must explicitly specify it in the DATABASE command. If you request read/write access to an analytic workspace that is being used in read/write mode by another session, whether or not OLAP Services waits for the analytic workspace and the message OLAP Services returns to the application depends on how you have coded the DATABASE command as described in "Waiting for an analytic workspace".

Waiting for an analytic workspace

You can specify whether or not you want to wait until an analytic workspace is available for the type of access you are you are requesting by using the WAIT and NOWAIT keywords of the DATABASE command.

• If you specify the NOWAIT keyword (the default) and if the analytic workspace is not available for the type of access you are requesting, then an error message is produced that indicates that the analytic workspace is unavailable.

• If you specify the WAIT keyword and the analytic workspace is not available for the type of access you are requesting, then OLAP Services places you on the wait list for the analytic workspace. The number of seconds that OLAP Services waits for access depends on the value of the DefaultDBWaitTime setting. Use the OLAP Services Instance Manager to change the value of the DefaultDBWaitTime setting.

Strategies for attaching analytic workspaces in exclusive mode

If your analytic workspaces are in use almost all of the time, you need to develop a strategy for attaching the analytic workspace in read/write, exclusive mode. Some possible strategies are listed below:

• "Officially" schedule a time to attach the analytic workspace exclusively.

• Run a batch job every 30 minutes or so that attempts to attach the analytic workspace in read/write, exclusive mode and, once it is successful, updates the analytic workspace. You can use the Persistent Session and Command line utilities to set up batch jobs.

Command line utilities

You can submit batch jobs using the OLAP Service Manager (xscosvc). You can define scripts that invoke xscosvc. You can schedule the running of these scripts with the Unix cron facility, the Windows NT at command, or the job-scheduling facility within Oracle Enterprise Manager. For more information about input files, refer to the INFILE command in the OLAP DML Reference.