17.6 Tuning other items
This section explains the tuning items other than those described till the previous section.
The following item is explained here:
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Tuning of the Persistent Connection
Determine the tuning of this item to use in-process HTTP servers in Web front-end systems.
In HTTP/1.1, a Persistent Connection is defined for the persistent use of the same TCP connection established between a Web client and Web server among multiple HTTP requests. Using a Persistent Connection, the time taken to establish a connection between a Web client and Web server can be shortened, and the communication traffic can be reduced.
However, the use of a Persistent Connection causes a specific Web client to occupy the request-processing threads, thereby leading to a decline in the processing performance of the entire server. Therefore, you are required to tune so as to be able to use the Persistent Connection effectively, and maintain the server processing performance.
When you use an in-process HTTP server, you can tune the following items of a Persistent Connection:
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Upper-limit value of the number of Persistent Connections
When a TCP connection exceeds this upper-limit value, it gets disconnected after the completion of request processing. Therefore, a thread can be secured for processing a new connection that can prevent the request-processing threads from being occupied by a specific client.
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Upper-limit value of the request-processing frequency of a Persistent Connection
Even when requests are received continuously from the same Web client, the TCP connection is disconnected once after the completion of request processing, if this upper-limit value is exceeded.
This can prevent the request-processing threads from being occupied by a specific client.
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Timeout of a Persistent Connection
You can set up timeouts for the request-waiting time of the Persistent Connection. If no processing request is received even after the lapse of the specified timeout period, the TCP connection will be disconnected. This can prevent the TCP connection from being occupied when it is not in use.
These items are specified as parameters of the Easy Setup definition file used with the Smart Composer functionality. The following table describes the tuning parameters to be set up for a Persistent Connection:
Setup item |
Location of setup |
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Upper-limit value of the number of Persistent Connections |
|
Upper-limit value of the request-processing frequency |
|
Timeout |
|
For details on each parameter, see 12.2 Parameters applicable to logical J2EE servers.