| In recent times, many netizens raised questions about Listener Configuration, and the client cannot connect to the server ). This article briefly introduces the Listener Configuration and provides some solutions for the failure of client terminals to connect to the server. It is helpful to the majority of users and readers.I,Listener (listener)Listener is a server-based network service of Oracle. It is mainly used to listen for connection requests from clients to database servers. Since it is a server-based service, it only exists on the database server, and listener settings are also completed on the database server.II,Local service name (tnsname)The connection between the Oracle client and the server is a connection request sent by the client. The server listener checks the client connection request legally. If the connection request is valid, the connection is performed. Otherwise, the connection is rejected. The local service name is a type of network configuration for the Oracle client, as well as the Oracle names server. The common client configuration in Oracle is the local service name. This article describes the configuration based on the local service name.III,OracleNetwork Connection configuration methodBoth the Oracle server and client can be configured in their own graphical Oracle Network Manager (Oracle Net manager) (we strongly recommend that you configure the Oracle server or client with this graphical tool ). In Windows, click Start/Program/Oracle-orahome92/configuration and migration tools/net manager to start the Oracle network manager tool. In Linux/Unix, run the netmgr command to start the graphical Oracle network manager. For example, run $ netmgrwindows to start the net manager graph window, as shown in figure (1)1. Oracle listener configuration (listener)As shown in figure (1), select the listener item in the tree directory, click "+" on the upper left side to add the listener, and click the listener directory, by default, the added listener name is listener (this name can also be named by any valid character ). Select the name, select "listener location" from the drop-down menu on the right of the window, and click the Add address button. Select "TCP/IP" from the Protocol drop-down option in the Network Address Bar, and enter the host name or IP address in the host text box (if the host is used as the server or as the client, either of the two items is valid. If the host acts as the server and needs to be connected over the network, we recommend that you enter an IP address.) in the port text box, enter a digital port. The default value is 1521, you can also customize any valid digital port. Figure 2 shows the configured listening position)Select "Database Service" from the drop-down list on the right of the window, and click "add Database. In the displayed database column, enter the global database name, for example, myoracle. Note that the global database name is different from the data warehouse Sid. The global database name actually controls the uniqueness of the global database name in the same network segment through the domain name, such as the domain name controller in windows, for example, enter myoracle.192.168.1.5. You can enter the SID for the Oracle main directory, for example, myoracle. Shows the complete database service configuration:
Figure (3) Save the preceding configurations. By default, the Listener Configuration File (for example, D: oracleora92networkadminlistener in Windows) can be found in the Oracle installation directory. ora, $ ORACLE_HOME/Network/admin/listerer in Linux/Unix. ora ). So far, the Listener Configuration for the Oracle server has been completed.2. Local Service name configuration (tnsnames)The local service name is based on the network configuration of the Oracle client. Therefore, if the client needs to connect to the database server for operations, you need to configure the client, the attached object can be any PC that wants to connect to the data warehouse server for operation, or the database server itself. As described earlier, you can use the net manager graphical management tool provided by Oracle to configure the Oracle client. Select the service name in (1), and click "+" in the upper left corner. The displayed dialog box is displayed. Figure (4) enter the net service name, such as myoracle, and click "Next, enter the displayed dialog box: Figure (5) Select TCP/IP (Internet Protocol) and click Next, as shown in:
Figure (6) enter the host name and port number. Note that the host name and port number must be the same as the host name and port number configured by the listener on the database server. Click Next, as shown in figure (7). Select the service name (Oracle8i or later) and enter the service name. The service name here is actually the global database name in the Listener Configuration of the database server. The former must be the same as the latter. The connection type is usually a dedicated server, which depends on the configuration of the database server. If the shared database server is configured, the connection type here must be a shared server, otherwise, we recommend that you select a dedicated server (for more information about the dedicated server, see the relevant documentation ). After configuration, click Next, as shown in figure (8). If the database server service is started, click test to test the connection. By default, Oracle uses Scott/tiger users to test connections. Since Scott is an example user of Oracle, this user may not be configured for formal business databases or professional Test Databases, therefore, you must change it to a valid user logon before the test is successful. If the connection fails, click "finish" to complete the configuration. Go back to the main window of Oracle Network Manager (Oracle Net manager) and save the configuration. By default, you can find the local service name configuration file in the Oracle Installation Directory (for example, D: oracleora92networkadmintnsnames in Windows. ora, $ ORACLE_HOME/Network/admin/tnsnames in Linux/Unix. ora ). The configured local service name is shown as follows:
Figure (9) the service name in the tree directory can be changed to a service name composed of any valid characters by renaming the menu in the editing menu. Note that the service name cannot contain spaces before it, otherwise, you may not be able to connect to the database server.3. Connect to the Database Server(1) Start the server listener and Database ServiceIn Linux/Unix, start the listener: $ LSNRCTL start close the listener: $ LSNRCTL stop view the listener status: $ LSNRCTL status start the database: $ sqlplus/nologsql> conn sys @ myoracle as sysdba -- Here myoracle is the local service name of the client configured earlier or SQL> Conn/As sysdbasql> startupwindows, start the listener: C: LSNRCTL start Oracle instance service: C: oradim? A href = "http://game.pchome.net/pcgame" class = "NONE" Title = "CS" rel = "external"> cstartup-Sid myoracle close Oracle instance service: C: oradim-shutdown-Sid myoracle and above services must be started at the same time, the client can connect to the database. Because the listener name configured by default is listener, the above command can start the listener normally. If the listener name is another name, such as alistener, you need to start the listener in the following ways: Linux/Unix: $ LSNRCTL start alistenerwindows: C: LSNRCTL start alistener(2) Test the connection to the Database ServerThe test methods are diverse. You can perform the test when configuring the local service name or a third-party client tool, such as PL/SQL developer. the most convenient way is to use the sqlplus tool that comes with Oracle, the following uses sqlplus for testing: C: sqlplus/nologsql> conn zgh @ myoracle is connected. IV,Troubleshooting of client connection to serverTo eliminate the connection problem between the client and the server, first check whether the client configuration is correct (the client configuration must be consistent with the database server listening configuration), and then solve the problem according to the error prompt. The following lists several common connection problems:1. ORA-12541: TNS: No listenerObviously, the server listener is not started, and check whether the client IP address or port is entered correctly. Start listener: $ LSNRCTL start or C: LSNRCTL start2. ORA-12500: TNS: The Listener cannot start the dedicated server processFor Windows, the Oracle instance service is not started. Start the instance service: C: oradim-startup-Sid myoracle3. ORA-12535: TNS: Operation timeoutThere are many reasons for this problem, but it is mainly related to the network. To solve this problem, first check whether the network between the client and the server is smooth. If the network is connected, check whether the firewalls at both ends have blocked the connection.4. ORA-12154: TNS: unable to process service nameCheck whether the entered service name is consistent with the configured service name. In addition, pay attention to the generated local service name file (for example, D: oracleora92networkadmin tnsnames in Windows. ora, Linux/Unix/Network/admin/tnsnames. the name of the first line of each service in ora cannot contain spaces.5. ORA-12514: TNS: the listener process cannot parse the SERVICE_NAME given in the connection DescriptorOpen net manager, select the service name, and check whether the service name entered in the service ID column is correct. The service name must be consistent with the global database name configured by the server listener.6. In Windows, when the listening service is started, the system prompts that the path cannot be found.You can run the command or start the listener in the service window. The system prompts that the path cannot be found, or the listening service has an exception. Open the registry, enter the HKEY_LOCAL_MACHINE/system/current ControlSet/services/oracleorahome92tnslistener item, and check whether the ImagePath string item exists. If not, set the value to D: oracleora92bintnslsnr, change the installation path values accordingly. This method is also applicable to Oracle instance services. In the same way, find the items like HKEY_LOCAL_MACHINE/system/current ControlSet/services/Oracle servicemyoracle to check whether the ImagePath string item exists. If not, create a new one, set the value to D: oracleora92 binoracle. EXE myoracle. The above are some common problems for Oracle clients to connect to the server. Of course, it cannot cover all connection exceptions. The key to solving the problem lies in the methods and ideas, rather than having fixed answers to each question.
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