5.1.3 Resources used by the database

This subsection describes the estimation of resources used by the DBMS.

For details about the estimation of memory used for each process, see 5.3 Estimating memory used for each process. For details about disk occupancy, see the Release notes of Application Server or Developer.

The following table describes the estimation of resources used by the DBMS:

Table 5‒8: Estimation of resources used by DBMS
DBMS	Used resources	Requirement
HiRDB	Maximum number of concurrent connections (`pd_max_users`)
Oracle	Maximum number of concurrent connections (`SESSIONS`)

#1

n is the total number of resource adapters deployed on the J2EE server in the system.

#2

Specifies the value of the MaxPoolSize parameter in the Connector property file.

#3

If one of the following conditions is applicable, multiply by 2:

Use XATransaction in the transaction support level.
Use a connection^# within the transaction that is managed by Application Server to access the database.
Before the transaction of step 2 concludes, use the connection^# outside the transaction to access the database.

# This connection is the one that is acquired from the DB Connector in step 1 and is the same connection.

#4

Add 1 only for the resource adapters with XATransaction specified in the transaction support level.

#5

The maximum value of + α is the total of the maximum values of the connection pools of the DB Connector you are using.

This value indicates connections that might temporarily exceed the maximum value for the connection pool. The details are as follows:

When using the functionality for detecting a connection failure

When implementing the functionality to detect a connection failure, the unused connections removed from a connection pool are not counted as the connections within the connection pool. Therefore, the total number of connections in a connection pool and the unused connections removed from the connection pool might temporarily exceed the maximum number of connections in the connection pool.
When using the cjclearpool command

In the normal mode, the connections being used that are removed from a connection pool are not included in the connection count. Therefore, the total number of connections in the connection pool and the used connections removed from the connection pool might exceed the maximum value for the connection pool.

To Page Top