12
Migration and Coexistence with Existing Gateways

Migration to new instances of Oracle Transparent Gateway for IBM DRDA from an existing installation is straightforward, provided some guidelines are followed. This chapter provides information to make these new installations as easy as possible.

This chapter provides information that is specific to this release of the Oracle Transparent Gateway for IBM DRDA, including the following sections:

Migrating Existing Gateway Instances to New Release

Follow these steps to migrate existing gateway instances to Oracle 9i.

Step 1: Install the new Release

Install the new release of the Gateway in a separate directory, as outlined in Chapter 4, "Installing the Gateway".

Warning:

Do not install the Gateway over a previously existing Gateway installation. Doing so will corrupt that existing installation.

Step 2: Transferring **initsid.gtwboot** Gateway Boot Initialization parameters.

In previous installations, two Gateway Initialization Files existed: initsid.gtwboot and initsid.ora. As mentioned in Chapter 8, "Configuring the Gateway", the parameters in the initsid.gtwboot have been moved to a Startup Shell Script. Copy the parameters from the initsid.gtwboot to the chosen Startup Shell Script and tailor them as needed. The format of the parameters can be found in the section "Startup Shell Script Parameters" in Appendix C, "DRDA-Specific Parameters".

Step 3: Transferring **initsid.ora** Gateway Initialization File parameters.

Copy the initsid.ora from the old Gateway instance to the new instance. The parameters in the initsid.ora Gateway Initialization File have changed format. Refer to "Gateway Initialization File Parameters" in Appendix C, "DRDA-Specific Parameters".

Backout Considerations When Migrating to New Releases

During the migration from older version 4 gateway instances to the latest Oracle 9i release, if problems are encountered, then it is always possible to revert to the previous version. Assuming a working version 4 gateway instance exists, simply change the TNSNAMES.ORA entries from using the Oracle 9i gateway instance to the older version 4 instance. Remember to remove the "(HS=)" entry from the SQL*Net connect definition.

Oracle recommends that when you are installing a new release of the gateway and upgrading existing instances, you keep the old gateway home and instance configurations intact and operational in case there are problems with the upgrade. This will help ensure minimal downtime between changes to different gateway instances.

New and Changed Parameters When Migrating from Version 4 to Release 9i of the Gateway

This release of the Oracle Transparent Gateway for IBM DRDA introduces new and changed initialization parameters if you are migrating from a Version 4 gateway to Oracle 9i.

Note:

The "New and Changed Parameters" section does not apply to you if you are migrating to Oracle 9i from Version 8 of the Oracle Transparent Gateway for IBM DRDA.

New Parameters

The following section lists new parameters relevant to migration from Version 4 gateways.

New Startup Shell Parameters

The following new Startup Shell parameters have been introduced in this release of the gateway. They must appear in the Startup Shell Script:

FDS_CLASS
FDS_INSTANCE

New Gateway Initialization File Parameters

Parameters introduced in this release of the gateway, listed in the following table, may be added to the Gateway Initialization File:

DRDA_CAPABILITY
DRDA_CMSRC_CM_IMMEDIATE
DRDA_DESCRIBE_TABLE
DRDA_LOCAL_NODE_NAME
DRDA_READ_ONLY
HS_RPC_FETCH_REBLOCKING
HS_FDS_FETCH_ROWS
HS_RPC_FETCH_SIZE
HS_NLS_NCHAR

Note:
The "HS_" parameters are specific to Oracle Heterogeneous Services. For details on HS parameters, refer to Oracle9i Heterogeneous Services.

Parameters That Have Been Changed in Usage

The following parameter's usage has changed with this release of the gateway:

DRDA_CONNECT_PARM

Parameters That Have Been Renamed

The following table (2 columns, 1 header row, 10 body rows) presents a list of parameters have been renamed with this release of the gateway, and their corresponding old names. Refer to Oracle9i Heterogeneous Services for more detailed information about these parameters.

New Name	Old Name
HS_COMMIT_STRENGTH_POINT	COMMIT_STRENGTH_POINT
HS_DB_DOMAIN	DB_DOMAIN
HS_DB_INTERNAL_NAME	DB_INTERNAL_NAME
HS_DB_NAME	DB_NAME
HS_DESCRIBE_CACHE_HWM	DESCRIBE_CACHE_HWM
HS_LANGUAGE	LANGUAGE
HS_NLS_DATE_FORMAT	NLS_DATE_FORMAT
HS_NLS_DATE_LANGUAGE	NLS_DATE_LANGUAGE
HS_OPEN_CURSORS	OPEN_CURSORS
HS_ROWID_CACHE_SIZE	ROWID_CACHE_SIZE

Obsolete Parameters

The following parameters are now obsolete. Please remove them from your configuration files:

MODE
SERVER_PATH
ERROR_LOGGING
ERROR_REPORTING
ERRORTAG
GATEWAY_SID
GROUP_BY_OFF
GTWDEBUG
INCREMENT_CURSORS

DRDA Server Considerations

Part of the normal installation for the gateway involves binding a package and (as an option) installing data dictionary views on the DRDA server. This release of the gateway (Release 9.0.1.0.1) is compatible with packages and views installed with the previous Version 8 and Version 4 releases. When migrating to the new release, you do not need to rebind existing packages or to re-install existing views in the DRDA server. However, this release of the gateway does have changes to the gateway tables and views which provide improved compatibility with Oracle server data dictionaries. It is recommended that you install the new tables and views as outlined in Chapter 8, "Configuring the Gateway". If you have modified certain DRDA parameters when migrating the gateway instance, then a rebind will be required of the package only. Appendix C lists the DRDA parameters which require a rebind if the value has been changed.

Oracle Net Considerations

The Gateway uses the Heterogeneous Services (HS) facilities of Oracle and Oracle Net. As such, gateway service name entries in the tnsnames.ora need a slight modification to tell Oracle Net that the gateway will be using the HS facilities. Refer to "Configuring Oracle Net" for detailed information.

12 Migration and Coexistence with Existing Gateways