4. Maintaining Connectivity

The Communications Server starts automatically when you start your Vector instance. Sometimes, however, it is necessary to stop the Communications Server.

You can start the local instance’s Communications Server using Visual Manager (IVM). For specific instructions, see IVM online help.

You can also start the Communications Server using the command line utilities.

To start the Communications Server at the command line

You can stop the local instance’s Communications Server using Visual Manager (IVM). For specific instructions, see IVM online help.

You can also stop the Communications Server using the command line utilities.

You can stop the local instance’s Communications Servers using Visual Performance Monitor. This “soft” shutdown operation waits for all sessions to end before stopping the server. Close the sessions (or ask users of those sessions to close them) before shutting down a server. For specific instructions, see Visual Performance Monitor online help.

To stop the communications server at the command line

Note: To increase the configured number of servers, you must reconfigure Ingres Net using Configuration Manager (vcbf) or the Configuration-By-Forms (cbf) utility.

A default number of 64 inbound and 64 outbound sessions are configured during the installation process. After the Communications Server has been running, you can change these default limits.

Resetting the maximum number of inbound and outbound sessions does not affect a currently running Communications Server. If you alter these figures after you start a Communications Server, you must stop and restart the server for the new limits to take effect.

The Ingres Net configuration parameters that determine the maximum number of allowed inbound and outbound sessions for a Communications Server are inbound_limit and outbound_limit.

The maximum values that you can assign to inbound_limit and outbound_limit are operating system dependent.

Linux: When setting inbound and outbound session limits, the maximum number of sessions that can be concurrently supported cannot exceed 14 less than the number of file descriptors allocated to each process. Each session uses two file descriptors, so there cannot be more sessions than half the total number of file descriptors. The following formula expresses the maximum number of connections that can be supported at any given time:

inbound_limit + outbound_limit <= (per_process_open_file_limit - 14) / 2

The number of file descriptors allocated to a process is a Linux kernel parameter (NOFILES on most platforms).

Windows: Vector uses the inbound_limit and outbound_limit values when it allocates resources. Consequently, if the sum of the new values is greater than the sum of the current values, you must shut down the instance (instead of only the Communications Server) and restart it so that the system can allocate the appropriate level of resources. If the sum of the new values is equal to or less than the sum of the current values, you can simply stop the Communications Server and restart it after you have reset the values.

The inbound_limit and outbound_limit parameters determine the maximum number of allowed inbound and outbound sessions for a Communications Server.

You can view or change the values for these parameters using the Parameters page for the selected Net Server in Configuration Manager (vcbf) or the Configure Net Server Definition screen in the Configuration-By-Forms (cbf) utility.

By default, Vector logs DBMS error messages, Ingres Net error messages, and Communications Server startup and shutdown messages to the errlog.log file.

The following logging level values are available:

(Default) Logs GCC START/STOP status messages, fatal GCC errors that cause the GCC process to stop, connection-specific errors that cause a specific connection to be broken, as well as logging level 1 messages

Logs connection setup and termination messages for all connections, as well as logging levels 4 and 1 messages.

Logging level is defined by the Ingres Net configuration parameter log_level.

To change the value of the log_level parameter, use the Parameters Page for the selected Net Server in Configuration Manager (vcbf) or the Configure Net Server Definition screen in the Configuration-By-Forms (cbf) utility.

During a session, each process or program queries the value of II_GCA_LOG when it starts up. If this environment variable/logical is set to a file name, the program sends its trace output to the specified file in addition to sending the output to the errlog.log. If you want to see the GCC trace output for a Communications Server, set II_GCA_LOG and stop and restart the Communications Server.

After you restart the Communications Server, unset II_GCA_LOG. You can leave II_GCA_LOG set, but you receive trace output for any process that starts after it was set.

To send the GCC information that is logged in errlog.log to another file in addition to the log file, follow this process:

GCF servers (Name Server, Communications Server, and Data Access Server) can be monitored using the iimonitor utility. The iimonitor utility can be used to:

For more information, see the iimonitor command in the “Command Reference” chapter of the User Guide.

A system administrator can define a default remote node for the local node. When this parameter is set, users are automatically connected to the default node whenever they request a connection without specifying a vnode name. If users want to access a database on their local node, they must specify the name configured as local_vnode on the Parameters Page, Name Server Component in Configuration Manager (vcbf) or the Configure Name Server screen in the Configuration-By-Forms (cbf) utility.

To illustrate, assume that the system administrator has set up the node “eugenie” as the default remote node for users at the node “josephine.” The node “eugenie” has the database “advertisers” and “josephine” has the database “employees.” Whenever users on “josephine” issue database connection requests that do not specify a vnode name, they are automatically connected to “eugenie” because “eugenie” is the default remote node for “josephine.” For example, look at the following statement:

If users on “josephine” issue this statement, Ingres Net automatically connects them to the “advertisers” database on “eugenie.” If the users on “josephine” want to query a local database, they must specify josephine’s local_vnode name. For example, if the local_vnode name for “josephine” is “royal,” users on “josephine” issue the following statement to query the local database “employees”:

Note: Do not set the default remote node name to point to a vnode that is in fact a loopback to the local instance. If you do so, your local connections loop through Ingres Net until all resources are exhausted and the connection fails.

To define a default remote node for the local node, set the configuration parameter remote_vnode on the Parameters Page, Name Server Component in Configuration Manager (vcbf) or the Configure Name Server screen in the Configuration-By-Forms (cbf) utility.

The DAS (iigcd) starts up automatically when you start up your Vector instance. Sometimes, however, it is necessary to stop the DAS. In such instances, you can use the following procedures to restart the server.

You can start the DAS using one of these methods:

• Using Actian Director to start the local instance's DAS. For instructions, see Director online help or User Guide.

You can stop the DAS using one of these methods:

• Using Visual Manager (IVM) to stop the local instance's DAS. For specific instructions, see IVM online help.