Oracle Transparent Gateway for Ingres II Administrator's Guide
Release 8.1.6

Part Number A82871-01

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4
Configuring the Gateway

After installing the gateway, perform the following tasks to configure the gateway for Ingres II:

Configuring the Gateway

Perform the following tasks to configure the Oracle Transparent Gateway for Ingres II.

Task 1: Choose a System ID for the Gateway

The gateway system identifier (SID) is an alphanumeric character string that identifies a gateway instance. You need one gateway instance, and therefore one gateway SID, for each Ingres II database you are accessing. The SID is used as part of the file name for the initialization parameter file. The default SID is tg4ingr.

You can define a gateway SID, but using the default of tg4ingr is easier because you do not need to change the initialization parameter file name. However, if you want to access two Ingres II databases, you need two gateway SIDs, one for each instance of the gateway. If you have one Ingres II database and want to access it sometimes with one set of gateway parameter settings, and other times with different gateway parameter settings, you can do that by having multiple gateway SIDs for the single Ingres II database.

Task 2: Customize the Initialization Parameter File

The initialization parameter file must be available when the gateway is started. During installation, the following default initialization parameter file is created:

$ORACLE_HOME/tg4ingr/admin/inittg4ingr.ora

where $ORACLE_HOME is the directory under which the gateway is installed.

If you are not using tg4ingr as the gateway SID, you must rename the initialization parameter file using the SID you chose in Task 1. This default initialization parameter file is sufficient for starting the gateway, verifying a successful installation, and running the demonstration scripts.

In the initialization parameter file, specify the Ingres II connection as follows:

HS_FDS_CONNECT_INFO=vnode::database_name

where vnode is the virtual node which will be used by the Ingres II client to access a remote networked Ingres II server. If you specify only database_name, omitting vnode, the gateway binds to the specified local database.

The entry for database_name is case-sensitive. You can specify an environment variable instead of the database name if your logical database is distributed among several physical databases. The Oracle Transparent Gateway for Ingres II translates the logical name before binding. For example, a logical name (ALL_SITES) can be defined to use as the database_name for a logical database distributed among two physical databases (BOSTON_DB and PARIS_DB), as follows in the UNIX C shell:

$ setenv ALL_SITES BOSTON_DB,PARIS_DB

Additionally, set the Ingres II environment variable, as follows:

SET II_SYSTEM=ingres_parent_dir

A number of initialization parameters can be used to modify gateway behavior. You might want to change the initialization parameter file later to meet system requirements.

See Also:

Appendix C, "Heterogeneous Services Initialization Parameters" and the Oracle8i Distributed Database Systems for more information about customizing the initialization parameter file. 

Configuring Net8 Listener for the Gateway

The gateway requires Net8 to provide transparent data access. After configuring the gateway, configure Net8 to work with the gateway.

Task 1: Configure Net8 TNS Listener for the Gateway

Net8 uses the TNS listener to receive incoming connections from a Net8 client. The TNS listener and the gateway must reside on the same machine.

The TNS listener listens for incoming requests from the Oracle database server. For the TNS listener to listen for the gateway, information about the gateway must be added to the TNS listener configuration file, listener.ora. This file is located in $ORACLE_HOME/network/admin, where $ORACLE_HOME is the $ORACLE_HOME directory under which the TNS listener is installed. This is the same $ORACLE_HOME directory under which the gateway is installed.


Note:

If Net8 is reinstalled, the original listener.ora file is renamed and a new listener.ora file is put into the $ORACLE_HOME/network/admin directory. 


The following entries must be added to the listener.ora file:

Example of Address to Listen On in listener.ora File

The Oracle database server accesses the gateway using Net8 and the TCP/IP protocol adapter. The following is the syntax of the connect descriptor entry in the listener.ora file:

LISTENER=
        (ADDRESS= 
          (PROTOCOL=TCP)
          (HOST=host_name)
          (PORT=port_number))

where:

host_name 

is the name of the machine on which the gateway is installed. 

port_number 

specifies the port number used by the TNS listener. If you have other listeners running on host_name, the value of port_number must be different from the other listeners' port numbers. 

Example of Gateway to Start in listener.ora File

To direct the TNS listener to start the gateway in response to incoming connection requests, add an entry to the listener.ora file with the following syntax:

SID_LIST_LISTENER=
   (SID_LIST=
      (SID_DESC= 
         (SID_NAME=gateway_sid)
         (ORACLE_HOME=oracle_home_directory)
         (PROGRAM=tg4ingr)
      )
   )

where:

gateway_sid 

specifies the SID of the gateway and matches the gateway SID specified in the connect descriptor entry in the tnsnames.ora file. 

oracle_home_directory 

specifies the Oracle home directory where the gateway resides. 

tg4ingr 

specifies the Oracle Transparent Gateway for Ingres II. 

If you are already running a TNS listener that listens on multiple database SIDs, add only the following syntax to SID_LIST in the existing listener.ora file:

SID_LIST_LISTENER=
(SID_LIST= 
   (SID_DESC=.
     .
   )
   (SID_DESC=.
     .
   )
   (SID_DESC=
      (SID_NAME=gateway_sid)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=tg4ingr)
   )
)

See Also:

Net8 Administrator's Guide for information about changing the listener.ora file. 

Task 2: Stop and Start the TNS Listener for the Gateway

The TNS listener must be started to initiate the new settings, as follows:

  1. Set the PATH environment variable to access the commands in the directory $ORACLE_HOME/bin where the gateway is installed. If you have the Bourne or Korn Shell, enter the following:

    $ PATH=$ORACLE_HOME/bin:$PATH;export PATH
    
    

    If you have the C Shell, enter the following:

    $ setenv PATH $ORACLE_HOME/bin:$PATH
    
    
  2. Set the LD_LIBRARY_PATH to include the Ingres II libraries. If you have the Bourne or Korn Shell, enter the following:

    $ set LD_LIBRARY_PATH=$II_SYSTEM/lib:$ORACLE_HOME/lib:$LD_LIBRARY_
    PATH;export LD_LIBRARY_PATH
    
    

    If you have the C Shell, enter the following:

    $ setenv LD_LIBRARY_PATH $II_SYSTEM/lib:$ORACLE_HOME/lib:$LD_LIBRARY_PATH
    
    


    Note:

    II_SYSTEM is an Ingres II environment variable. See your Ingres II documentation for information about setting the environment variables to access the Ingres II database. 


  3. If the listener is already running, use the lsnrctl command to stop the listener and then start it with the new settings, as follows:

    $ lsnrctl stop
    $ lsnrctl start
  4. Check the status of the listener with the new settings, as follows:

    $ lsnrctl status
    
    

    The following is an example of output from a lsnrctl status check:

    Connecting to (ADDRESS=(PROTOCOL=TCP)(HOST=204.179.99.15)(PORT=1551))
    STATUS of the LISTENER
    ----------------------
    Alias LISTENER
    Version TNSLSNR for Solaris: Version 8.1.6.0.0 - Production
    Start Date 05-DEC-1999 14:07:29
    Uptime 0 days 21 hr. 9 min. 25 sec
    Trace Level off
    Security OFF
    SNMP OFF
    Listener Parameter File /parla/test40/ingr/network/admin/listener.ora
    Listener Log File /parla/test40/ingr/network/log/listener.log
    Services Summary...
    tg4ingr has 1 service handler(s)
    The command completed successfully

    In this example, tg4ingr is the default SID value assigned during installation. You can use any valid ID for the SID, or keep the default.


    Note:

    You must use the same SID value in the tnsnames.ora file, the listener.ora file. 


Configuring the Oracle Database Server for Gateway Access

Any Oracle client connected to the Oracle database server can access Ingres II data through the gateway. The Oracle client and the Oracle database server can reside on different machines. The gateway accepts connections only from the Oracle database server.

Before you use the gateway to access Ingres II data you must configure the Oracle database server to enable communication with the gateway over Net8.

Configuring Oracle Net8 for the Oracle Database Server

To configure the server you add connect descriptors to the tnsnames.ora file. You cannot use the Net8 Assistant or the Net8 Easy Config tools to configure the tnsnames.ora file. You must edit the file manually.

See Also:

Oracle8i Administrator's Guide for information about editing the tnsnames.ora file

For the Oracle database server to access the gateway, it needs a service name entry or a connect descriptor name entry in the tnsnames.ora file to tell the Oracle database server where to make connections. By default, this file is in $ORACLE_HOME/network/admin, where $ORACLE_HOME is the directory in which the Oracle database server is installed. The tnsnames.ora file is required by the Oracle database server accessing the gateway, but not by the gateway.

Configuring tnsnames.ora

Edit the tnsnames.ora file to add a connect descriptor for the gateway. The following is an example of the Net8 entries using TCP/IP protocol needed for the Oracle database server to access the gateway:

connect_descriptor=
   (DESCRIPTION=
      (ADDRESS=
         (PROTOCOL=TCP)
         (HOST=host_name)
         (PORT=port_number)
      )
      (CONNECT_DATA=
         (SID=gateway_sid))
      (HS=OK))

where:

connect_descriptor 

is the description of the object to connect to as specified when creating the database link, such as tg4ingr.

Check the sqlnet.ora file in the Oracle database server's $ORACLE_HOME for the following lines:

  • names.directory_path = (TNSNAMES, HOSTNAME)

  • names.default_domain = world

  • name.default_zone = world

Note: If the Oracle database server is on Sun SPARC Solaris, the file is $ORACLE_HOME/network/admin/sqlnet.ora.

If the sqlnet.ora file has these lines, connect_descriptor must end with the extension .world

TCP 

is the TCP protocol used for TCP/IP connections. 

host_name 

specifies the machine where the gateway is running. 

port_number 

matches the port number used by the Net8 TNS listener that is listening for the gateway. The TNS listener's port number can be found in the listener.ora file used by the TNS listener. See "Example of Address to Listen On in listener.ora File" on page 4-4

gateway_sid 

specifies the SID of the gateway and matches the SID specified in the listener.ora file of the TNS listener that is listening for the gateway. See "Task 1: Configure Net8 TNS Listener for the Gateway" on page 4-3 for more information. 

(HS=OK) 

specifies that this connect descriptor uses the Oracle Heterogeneous Services option. 

Performing Optional Configuration Tasks

You can perform the following configuration tasks:

Configuring for Two-Phase Commit

The gateway supports the following transaction capabilities:

By default, the gateway runs in COMMIT_CONFIRM transaction mode. When the Ingres II database is updated by a transaction, the gateway becomes the commit point site. The Oracle database server commits the unit of work in the Ingres II database after verifying that all Oracle databases in the transaction have successfully prepared the transaction. Only one gateway can participate in an Oracle two-phase commit transaction as the commit point site.

See Also:

Oracle8i Distributed Database Systems for information about the two-phase commit process. 

To enable the COMMIT_CONFIRM transaction mode, create a recovery account and password and create a log table. The log table, called HS_TRANSACTION_LOG, is where two-phase commit transactions are recorded.

Task 1: Create a Recovery Account and Password

For the gateway to recover distributed transactions, a recovery account and password must be set up in the Ingres II database. By default, both the user name of the account and the password are RECOVER. The name of the account can be changed with the gateway initialization parameter HS_FDS_RECOVERY_ACCOUNT. The account password can be changed with the gateway initialization parameter HS_FDS_RECOVERY_PWD.


Note:

Oracle Corporation recommends that you use the default value RECOVER for the user name and password. 


  1. Set up a user account in the Ingres II database. Both the user name and password must be a valid Ingres II user name and password.

  2. In the initialization parameter file, set the following gateway initialization parameters:

Task 2: Create the Transaction Log Table

When configuring the gateway for two-phase commit, a table must be created in the Ingres II database for logging transactions. The gateway uses the transaction log table to check the status of failed transactions that were started at the Ingres II database by the gateway and registered in the table. Updates to the transaction log table cannot be part of an Oracle distributed transaction.


Note:

The information in the transaction log table is required by the recovery process and must not be altered. The table must be used, accessed, or updated only by the gateway. 


The table consists of two columns, GLOBAL_TRAN_ID, data type CHAR(64) NOT NULL and TRAN_COMMENT, data type CHAR(255).

Create a transaction log table in the user account you created in "Task 1: Create a Recovery Account and Password". Because the transaction log table is used to record the status of a gateway transaction, the table must reside at the database where the Ingres II update takes place. Also, the transaction log table must be created under the owner of the recovery account.


Note:

To utilize the transaction log table, users of the gateway must be granted privileges on the table. 


To create a transaction log table use the tg4ingr_tx.sql script, located in the directory $ORACLE_HOME/tg4ingr/admin where $ORACLE_HOME is the directory under which the gateway is installed. Use isql to execute the script, as follows:

$ isql -Urecovery_account -Precovery_account [-Sserver] -itg4ingr_tx.sql

Creating Database Links

Any Oracle client connected to the Oracle database server can access Ingres II data through the gateway. The Oracle client and the Oracle database server can reside on different machines. The gateway accepts connections only from the Oracle database server.

A connection to the gateway is established through a database link when it is first used in an Oracle session. In this context, a connection refers to the connection between the Oracle database server and the gateway. The connection remains established until the Oracle session ends. Another session or user can access the same database link and get a distinct connection to the gateway and Ingres II database.

Database links are active for the duration of a gateway session. If you want to close a database link during a session, you can do so with the ALTER SESSION statement. The database and application administrators of a distributed database system are responsible for managing the necessary database links that define paths to the Ingres II database.

See Also:

Oracle8i Administrator's Guide and Oracle8i Distributed Database Systems for more information about using database links. 

Configuring the Gateway for Multiple Ingres II Databases

The tasks for configuring the gateway to access multiple Ingres II databases are similar to the tasks for configuring the gateway for a single database. The configuration example assumes the following:

Configuring the gateway for additional Ingres II databases is similar to configuring it for one database, and involves the following:

Multiple Databases Example: Configuring the Gateway

Choose Two System IDs for Each Ingres II Database

A separate instance of the gateway accesses the different Ingres II databases. Each instance needs its own gateway System ID (SID). For this example, the gateway SIDs are chosen for the instances that access the Ingres II databases:

Create Two Initialization Parameter Files

Create an initialization parameter file for each instance of the gateway by copying the original initialization parameter file,
$ORACLE_HOME/tg4ingr/admin/inittg4ingr.ora, twice, naming one with the gateway SID for db2 and the other with the gateway SID for db3:

$ cd $ORACLE_HOME/tg4ingr/admin
$ cp inittg4ingr.ora inittg4ingr2.ora
$ cp inittg4ingr.ora inittg4ingr3.ora

Change the value of the HS_FDS_CONNECT_INFO parameter in the new files.

For inittg4ingr2.ora, enter the following:

HS_FDS_CONNECT_INFO=db2

For inittg4ingr3.ora, enter the following:

HS_FDS_CONNECT_INFO=db3


Note:

If you have multiple gateway SIDs for the same Ingres II database because you want to use different gateway parameter settings at different times, follow the same procedure. You create several initialization parameter files, each with different SIDs and different parameter settings. 


Multiple Databases Example: Configuring the Ingres II Environment

Set the Ingres II environment variables in both of the new initialization parameter files, as follows:

For inittg4ingr2.ora, enter the following:

SET II_SYSTEM=ingres_parent_dir

For inittg4ingr3.ora, enter the following:

SET II_SYSTEM=ingres_parent_dir

Multiple Databases Example: Configuring Oracle Net8 Listener

Add Entries to listener.ora

Add two new entries to the TNS listener configuration file, listener.ora. You must have an entry for each gateway instance, even when multiple gateway instances access the same database.

The following example shows the entry for the original installed gateway first, followed by the new entries:

SID_LIST_LISTENER=
(SID_LIST=
   (SID_DESC=
      (SID_NAME=tg4ingr)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=tg4ingr)
   )
   (SID_DESC=
      (SID_NAME=tg4ingr2)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=tg4ingr)
   )
   (SID_DESC=
      (SID_NAME=tg4ingr3)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=tg4ingr)
   )
)

Multiple Databases Example: Stopping and Starting the TNS Listener

The LD_LIBRARY_PATH environment variable must be set to include the Ingres II libraries and the TNS listener must be started to initiate the new settings.

If you have the Bourne or Korn Shell, to set the LD_LIBRARY_PATH enter the following:

$ set LD_LIBRARY_PATH=$II_SYSTEM/lib:ORACLE_HOME/lib:$LD_LIBRARY_PATH;export LD_
LIBRARY_PATH

If you have the C Shell, enter the following:

$ setenv LD_LIBRARY_PATH $II_SYSTEM/lib:ORACLE_HOME/lib:$LD_LIBRARY_PATH


Note:

II_SYSTEM is an Ingres II environment variable. See your Ingres II documentation for information about setting the environment variables to access the Ingres II database. 


If the listener is already running, use the lsnrctl command to stop the listener and then start it with the new settings, as follows:

$ lsnrctl stop
$ lsnrctl start

Multiple Databases Example: Configuring the Oracle Database Server for Gateway Access

Configuring Net8 on the Oracle Database Server for Multiple Gateway Instances

Add two connect descriptor entries to the tnsnames.ora file. You must have an entry for each gateway instance, even if the gateway instances access the same database.

The following Ingres II example shows the entry for the original installed gateway first, followed by the two entries for the new gateway instances:

old_db_link=(DESCRIPTION=
              (ADDRESS=
                (PROTOCOL=TCP)
                (PORT=1541)
                (HOST=gtwhost))
                (CONNECT_DATA=
                    (SID=tg4ingr))
               (HS=OK))
new_db2_link=(DESCRIPTION=
              (ADDRESS=
                (PROTOCOL=TCP)
                (PORT=1541)
                (HOST=gtwhost))
                (CONNECT_DATA=
                    (SID=tg4ingr2))
                (HS=OK))
new_db3_link=(DESCRIPTION=
              (ADDRESS=
                (PROTOCOL=TCP)
                (PORT=1541)
                (HOST=gtwhost))
                (CONNECT_DATA=
                    (SID=tg4ingr3))
                (HS=OK)) 

The value for PORT is the TCP/IP port number of the TNS listener that is listening for the gateway. The number can be found in the listener.ora file used by the TNS listener. The value for HOST is the name of the machine on which the gateway is running. The name also can be found in the listener.ora file used by the TNS listener.

Multiple Databases Example: Accessing Ingres II Data

Enter the following to create a database link for the tg4ingr2 gateway:

SQL> CREATE PUBLIC DATABASE LINK INGR2 CONNECT TO
  2  user2 IDENTIFIED BY password2 USING 'tg4ingr2';

Enter the following to create a database link for the tg4ingr3 gateway:

SQL> CREATE PUBLIC DATABASE LINK INGR3 CONNECT TO
  2  user3 IDENTIFIED BY password3 USING 'tg4ingr3';

After the database links are established you can query the new Ingres II databases, as in the following:

SQL> SELECT * FROM ALL_USERS@INGR2;

or

SQL> SELECT * FROM ALL_USERS@INGR3;


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