Oracle共享服务器配置

    oralce网络连接可以有专用服务器进程（Dedicated Processes）和共享服务器进程（Shared Server Processes）两种模式：
A dedicated server process, which services only one user process；
A shared server process, which can service multiple user processes。

The following initialization parameters control shared server operation:（以下参数是用于共享服务器进程设置）
■ SHARED_SERVERS: Specifies the initial number of shared servers to start and the
minimum number of shared servers to keep. This is the only required parameter
for using shared servers.（最重要的参数，设置共享进程的最小值，只要该值大于0，则启动共享模式，
其实共享模式和专用模式是并存的，但默认是共享模式，进程名称：ora_s001_sid）

■ MAX_SHARED_SERVERS: Specifies the maximum number of shared servers that
can run simultaneously.（设置共享进程的最大值）

■ SHARED_SERVER_SESSIONS: Specifies the total number of shared server user
sessions that can run simultaneously. Setting this parameter enables you to reserve
user sessions for dedicated servers.（设置共享进程支持的最大会话数，用于保留可用的专用模式连接。）

■ DISPATCHERS: Configures dispatcher processes in the shared server architecture.
（设置分发器的个数，进程名称：ora_d001_sid）

■ MAX_DISPATCHERS: Specifies the maximum number of dispatcher processes that
can run simultaneously. This parameter can be ignored for now. It will only be
useful in a future release when the number of dispatchers is auto-tuned according
to the number of concurrent connections.
(设置分发器的最大个数)

■ CIRCUITS: Specifies the total number of virtual circuits that are available for
inbound and outbound network sessions.
（设置共享模式的最大的连接数）

共享模式可以在动态设定，具体步骤如下：
服务器端：
1.设定shared_servers为非零值：
alter system set shared_servers=2;

2.设定dispatchers为正确值：
alter system set dispatchers='(PROTOCOL=TCP)(SERVICE=your_sid)(DISPATCHERS=2)';

客户端：
默认模式：
DEFAULT =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 1.1.1.242)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = balance)
    )
)

专用模式：
DEDICATED =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 1.1.1.242)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = balance)
    )
)

共享模式：
SHARED =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 1.1.1.242)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = SHARED)
      (SERVICE_NAME = balance)
    )
)

连接：
sqlplus
sqlplus
sqlplus