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Performance Tuning Guide > Tuning the Siebel Application Object Manager for Performance > Configuring Database Connection Pooling for AOMs > Configuring Pooling for Default Database ConnectionsDefault database connections can be used by most AOM operations. Configuring Parameters for Pooling Default ConnectionsThis section describes how to enable or disable pooling for default database connections using the parameters MaxSharedDbConns (DB Multiplex - Max Number of Shared DB Connections) and MinSharedDbConns (DB Multiplex - Min Number of Shared DB Connections).
MaxSharedDbConns and MinSharedDbConns are defined per AOM component, on an enterprise basis (these parameters are included in named subsystems of type InfraDatasources). The database connections these parameters control are not shared across multithreaded processes. The actual maximum number of database connections for each multithreaded process is determined by the ratio MaxSharedDbConns/MaxMTServers. NOTE: MaxSharedDbConns and MinSharedDbConns work differently than MinTrxDbConns, which specifies the number of shared specialized database connections available for each multithreaded process. For details, see Configuring Pooling for Specialized Database Connections. Example Configuration for Pooling Default ConnectionsAssume, for example, the following parameter settings: MaxTasks = 500 With these settings, the AOM component can support a maximum of 500 tasks (threads). Those 500 tasks would be spread over five multithreaded processes, each having 100 tasks. Each multithreaded process would have a maximum of 50 shared database connections, each of which would serve up to two tasks. How Pooled Default Connections Are AssignedWhen the AOM starts up, the shared connection pool is empty. When a user logs into the AOM, the shared connection pool is checked to see if a connection is available. Shared database connections may be assigned to a new user session in any of the following ways:
Once a shared connection is assigned to the new session, all database operations (read, write, update, and delete) for the session go through the connection. When the session terminates, the usage count for the database connection is decremented. If the usage count has reached 0 (no sessions use this connection) and there are at least MinSharedDbConns connections already in the pool, the connection is removed from the pool and closed. Otherwise, it is left in the pool so the minimum number of shared connections is maintained. When an AOM multithreaded process shuts down, any remaining connections in the pool that were managed by this process are closed. Scenario for Assigning Pooled Default ConnectionsAssuming, for example, the parameter settings described in Example Configuration for Pooling Default Connections, shared database connections will be handled as in the following scenario:
For details, see How Pooled Default Connections Are Assigned. |
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