The number of user processes that can simultaneously connect to the Oracle database is limited by the PROCESSES initialization parameter of the Oracle database instance. For an application, the value of this parameter depends on the connection pool size parameter of that application. Each Financial Management application requires a minimum of 20 database connections, plus the Financial Management database connection pool setting value. For example, if the Financial Management database connection pool setting is 40, then each Financial Management application requires at least 60 Oracle database connections. As a result, the value of PROCESSES should be set higher than 60.
Note: | The total number of servers in a cluster, and the total number of applications, affect the number of required database connections. |
This example illustrates how to calculate the number of processes that connect to the Oracle database. Suppose a cluster of two Financial Management application servers has two applications on each server. The Financial Management database connection pool setting is 40. The minimum number of Oracle database connections is calculated as the sum of the connection pool setting plus 20, times the number of applications, times the number of application servers: (40 + 20) * 2 * 2 = 240. For additional safety, multiply this number by a factor of 1.1 to allow for ancillary connections and general usage of the database. Considering that the Oracle database also has some background processes, add 20 to this number to arrive at the value of PROCESSES. So, in this case, PROCESSES should be set to 260.
In general,
PROCESSES = (Financial Management connection pool setting + 20) * (Number of Financial Management applications) * (Number of Financial Management application servers) * 1.1 + 20.