How Leases are Implemented

Essbase failover implements a leasing mechanism using a centralized relational database to store, update, and retrieve information about the following:

The set of tables used for this purpose is created during Essbase installation and configuration. These tables reside in the same database and schema as the Shared Services Registry.

On startup, Essbase Agent and servers inspect the database table to see if any other process currently owns the lease for its shared resource . If yes, the agent and servers wait until the lease expires and retries. If not, the agent and servers take ownership of the shared resource; that is, they get a lease.

The agent and servers acquires a lease on startup and surrender the lease on termination. The agent and servers periodically renew the lease to indicate its health. If the lease cannot be renewed, the agent and servers self-terminate.

Lease ownership grants exclusive right to update a set of shared resources residing on a shared disk. The lease owner (Essbase Agent or Essbase Server) attempts to renew the lease within a preconfigured interval of time. See the AGENTLEASERENEWALTIME and SERVERLEASERENEWALTIME configuration settings in the Oracle Essbase Technical Reference.