2 Oracle GoldenGate Veridata Prerequisites and System Requirements

Before you begin the installation, find out the minimum system and network requirements and what pre-installation tasks you must first complete.

This chapter includes the following sections:

2.1 General Information

Oracle GoldenGate Veridata does not require an installation of the Oracle GoldenGate replication software. If you do use that software, then install Oracle GoldenGate Veridata in a different location.

Oracle GoldenGate Veridata is designed to run on dedicated hardware to utilize all available CPUs and memory. Oracle recommends that you do not run any other application on the same host where the Oracle GoldenGate Veridata Server is installed.

2.2 Prerequisites for Installing Oracle GoldenGate Veridata

This section describes the prerequisites you must meet before you can successfully install and configure Oracle GoldenGate Veridata. The following sections explain the prerequisites:

2.2.1 Verifying Certification, System, and Interoparability Requirements

Oracle recommends that you use the certification matrix and system requirements documents with each other to verify that your environment meets the requirements for installation.

  1. Verifying that your environment meets certification requirements:

    Make sure that you install your product on a supported hardware and software configuration. See the certification document for your release on the Oracle Fusion Middleware Supported System Configurations page.

    Oracle has tested and verified the performance of your product on all certified systems and environments. Whenever new certifications are released, they are added to the certification document right away. New certifications can be released at any time. Therefore, the certification documents are kept outside the documentation libraries and are available on Oracle Technology Network.

  2. Using the system requirements document to verify certification:

    Oracle recommends that you use the Oracle Fusion Middleware System Requirements and Specifications document to verify that the certification requirements are met. For example, if the certification document indicates that your product is certified for installation on 64-Bit Oracle Linux 6.5, use this document to verify that your system meets the required minimum specifications. These include disk space, available memory, specific platform packages and patches, and other operating system-specific requirements. System requirements can change in the future. Therefore, the system requirement documents are kept outside of the documentation libraries and are available on Oracle Technology Network.

  3. Verifying interoperability among multiple products:

    To learn how to install and run multiple Fusion Middleware products from the same release or mixed releases with each other, see Oracle Fusion Middleware Interoperability and Compatibility in Oracle Fusion Middleware Understanding Interoperability and Compatibility.

2.2.2 Selecting an Installation User

The user who installs and configures your system must have the required permissions and privileges.

2.2.2.1 About User Permissions

The user who installs a Fusion Middleware product has the following permissions on them:

  • Read and write permissions on all non-executable files (for example, .jar, .properties, or .xml). All other users in the same group as the file owner have read permissions only.

  • Read, write, and execute permissions on all executable files (for example, .exe, .sh, or .cmd). All other users in the same group as the file owner have read and execute permissions only.

This means that someone other than the person who installs the software can use the installed binaries in the Oracle home to configure a domain or set of Fusion Middleware products.

Below are some additional considerations to make prior to running the installer:

  • On UNIX operating systems, Oracle recommends that you set the umask to 027 on your system prior to installation. This ensures that file permissions are set properly during installation. Use the following command:

    umask 027

    You must enter this command in the same terminal window from which you plan to run the product installer.

  • On UNIX operating systems, do not run the installation program as the root user. The installer startup validation will fail and you will not be able to continue.

  • When managing a product installation (for example, applying patches), you must use the same user ID as was used to perform the initial product installation.

  • On Windows operating systems, the user performing the installation must have Administrator privileges. See Verifying that the Installation User has Administrator Privileges on Windows Operating Systems.

2.2.2.2 About Non-Default User Permissions on UNIX Operating Systems

Changing the default permission setting reduces the security of the installation and your system. Oracle does not recommend you to change the default permission settings.

If other users require access to a particular file or executable, use the UNIX sudo command or other similar commands to change the file permissions.

Refer to your UNIX operating system Administrator's Guide or contact your operating system vendor, if you need further assistance.

2.2.2.3 Verifying that the Installation User has Administrator Privileges on Windows Operating Systems

By default, users with the administrator privilege sign in to the system with regular privileges, but can request elevated permissions to perform administrative tasks.

To perform a task with elevated privileges:

  1. Find the Command Prompt icon, either from the Start menu or the Windows icon in the lower-left corner.
  2. Right-click Command Prompt and select Run as administrator.
    This opens a new command prompt window, and all actions performed in this window are done with administrator privileges.

    Note:

    If you have User Access Control enabled on your system, you may see an additional window asking you to confirm this action. Confirm and continue with this procedure.

    Note:

    For Oracle Internet Directory, ensure that you have enabled User Account Control (UAC). If you have not done so already, enable UAC by following the instructions in the Enabling User Account Control (UAC) section from the appropriate version of Oracle Fusion Middleware System Requirements and Specifications for your installation.

    Note:

    For Oracle Identity and Access Management components, ensure that you have enabled User Account Control (UAC). If you have not done so already, enable UAC by following the instructions in the Enabling User Account Control (UAC) section from the appropriate version of Oracle Fusion Middleware System Requirements and Specifications for your installation.
  3. Perform the desired task.

    For example, to start the product installer:

    For a jar file, enter:

    java —jar distribution_name.jar

    For an executable (.exe, .bin, or .sh file), enter:

    distribution_name.exe

2.2.3 About the Oracle Home Directory

After installing the certified JDK for your operating system, use the Oracle Fusion Middleware 12.2.1.4.0 Infrastructure installer to install Oracle WebLogic Server 12.2.1.4.0 and the Oracle Java Required Files (JRF) Infrastructure services.

When you install any Oracle Fusion Middleware product, you must use an Oracle home directory.

This directory is a repository for common files that are used by multiple Fusion Middleware products installed on the same machine. These files ensure that Fusion Middleware operates correctly on your system. They facilitate checking of cross-product dependencies during installation. For this reason, you can consider the Oracle home directory a central support directory for all Oracle Fusion Middleware products installed on your system. Fusion Middleware documentation refers to the Oracle home directory as ORACLE_HOME.

Oracle Home Considerations

  • Do not include spaces in the name of your Oracle home directory; the installer displays an error message if your Oracle home directory path contains spaces.
  • You can install only one instance of each Oracle Fusion Middleware product in a single Oracle home directory. If you need to maintain separate versions of a product on the same machine, each version must be in its own Oracle home directory.
Although you can have several different products in a single Oracle home, only one version of each product can be in the Oracle home.

Multiple Home Directories

Although in most situations, a single Oracle home directory is sufficient, it is possible to create more than one Oracle home directory. For example, you need to maintain multiple Oracle home directories in the following situations:
  • You prefer to maintain separate development and production environments, with a separate product stack for each. With two directories, you can update your development environment without modifying the production environment until you are ready to do so.
  • You want to maintain two different versions of a Fusion Middleware product at the same time. For example, you want to install a new version of a product while keeping your existing version intact. In this case, you must install each product version in its own Oracle home directory.
  • See Oracle Fusion Middleware Understanding Interoperability and Compatibility .

Note:

If you create more than one Oracle home directory, you must provide non-overlapping port ranges during the configuration phase for each product.

2.2.4 About JDK Requirements for an Oracle Fusion Middleware Installation

Most Fusion Middleware products are in .jar file format. These distributions do not include a JDK. To run a .jar distribution installer, you must have a certified JDK installed on your system.

Make sure that the JDK is installed outside of the Oracle home. If you install the JDK under the Oracle home, you may encounter problems when you try to perform tasks in the future. Oracle Universal Installer validates that the Oracle home directory is empty; the install does not progress until you specify an empty directory. Oracle recommends that you locate your JDK installation in the /home/oracle/products/jdk directory.

Platform-specific distributions have a .bin (for UNIX operating systems) or .exe (for Windows operating systems) installer; in these cases, a platform-specific JDK is in the distribution and you do not need to install a JDK separately. However, you may need to upgrade this JDK to a more recent version, depending on the JDK versions that are certified.

Always verify the required JDK version by reviewing the certification information on the Oracle Fusion Middleware Supported System Configurations page. For 12c (12.2.1.4.0), the certified JDK is 1.8.0_221 and later.

To download the required JDK, navigate to the following URL and download the Java SE JDK:

http://www.oracle.com/technetwork/java/javase/downloads/index.html.

2.2.5 About Database Requirements for an Oracle Fusion Middleware Installation

Many Oracle Fusion Middleware products require database schemas prior to configuration. If you do not already have a database where you can install these schemas, you must install and configure a certified database.

Note:

Multi-tenancy feature is supported, that is, Pluggable Database (PDB) and Container Database (CDB) are supported.

To find a certified database for your operating system, see the certification document for your release on the Oracle Fusion Middleware Supported System Configurations page on the Oracle Technology Network (OTN).

To make sure that your database is properly configured for schema creation, see Repository Creation Utility Requirements in the Oracle Fusion Middleware System Requirements and Specifications document.

After your database is properly configured, you use the Repository Creation Utility (RCU) to create product schemas in your database. This tool is available in the Oracle home for your Oracle Fusion Middleware product. See About the Repository Creation Utility in Oracle Fusion Middleware Creating Schemas with the Repository Creation Utility.

Note:

Based on your deployment topology and the work load, it is recommended that you refer to the following note on My Oracle Support, and take appropriate actions for your deployment.

Performance Tuning Guidelines and Diagnostics Collection for Oracle Identity Manager (OIM) (Doc ID 1539554.1)

2.3 Supported Databases for Compare

Oracle GoldenGate Veridata supports the following databases for comparisons:

  • Oracle, ADW, ATP, DBCS
  • SQL Server
  • MySQL
  • Teradata
  • BigData Hive
  • DB2 for i, DB2 LUW, and DB2 z/OS
  • Informix
  • Non Stop (Enscribe, SQL/MP, SQL/MX)
  • Sybase Adaptive Server Enterprise (ASE)

Through its support website, Oracle provides late-breaking updates, discussions, and best practices about pre-upgrade requirements, upgrade processes, post-upgrade, compatibility, and interoperability. To find the latest information about Oracle GoldenGate Veridata release, including the list of certified database versions and operating systems, go to My Oracle Support at http://support.oracle.com.

2.4 Supported/Unsupported Databases for Repair

Oracle GoldenGate Veridata supports the following databases for repair functionality:

  • Oracle, ADW, ATP, DBCS
  • SQL Server
  • Teradata
  • DB2 for i, DB2 LUW, and DB2 z/OS
  • Informix
  • Sybase Adaptive Server Enterprise (ASE)
  • MySQL
  • Non Stop (Enscribe, SQL/MP)

Oracle GoldenGate Veridata doesn't support the following databases for repair functionality, but supported by Oracle GoldenGate:

  • Non Stop (SQL/MX)
  • BigData Hive

Oracle provides late-breaking updates, discussions, and best practices about pre-upgrade requirements, upgrade processes, post-upgrade, compatibility, repair, and interoperability. For information about the latest release of Oracle GoldenGate Veridata, including the list of certified database versions and operating systems, go to My Oracle Support at http://support.oracle.com. For the support/certification matrix for the supported versions of databases at Oracle Support website or at http://www.oracle.com/technetwork/middleware/ias/downloads/fusion-certification-100350.html.

2.5 Oracle GoldenGate Veridata Agent System Requirements

One Oracle GoldenGate Veridata Agent must be installed for each database instance that contains data that is to be compared. At minimum, therefore, you will install two agents — one to retrieve source rows and one to retrieve target rows (unless you are comparing data within the same database instance). One agent can retrieve rows from multiple databases or schemas within a given database instance. However, one agent cannot retrieve rows from different database instances.

Comparing Multi-Byte Data

The following considerations apply when you are comparing tables with multibyte data:

  • A Java agent should be used for all platforms except NonStop, which has only a C-agent.

  • The Java agent uses the UTF-8 character for comparing character data. Out-of-sync data is written to the report file using the UTF-8 character set.

  • The Oracle GoldenGate Veridata Oracle C-Agent can be used for comparisons between Oracle databases where the source and target use the same character set and the host system uses the same byte order. An Oracle C-Agent cannot be used in a comparison with a Java agent. Character fields that contain characters that are not valid UTF-8 characters are displayed as hexadecimal in the out-of-sync reports.

2.5.1 Oracle GoldenGate Veridata Java Agent

Oracle GoldenGate Veridata provides a Java-based agent for the following databases:

  • DB2 for i, DB2 LUW, and DB2 z/OS

  • Oracle

  • SQL Server

  • Sybase ASE

  • Teradata

  • Informix

  • BigData Hive

The Java agent connects to the database by using JDBC (Java Database Connectivity). The Java agent enables Oracle GoldenGate Veridata to support comparisons in a heterogeneous environment, where different kinds of databases contain similar, but not identical data types. With a Java agent, one executable supports many operating systems and databases.

You can install the Java agent on the same system as the one where the database is running, or you can install it on a different system, such as the one where Oracle GoldenGate Veridata Server is installed. When considering where to install the agent, weigh the additional and significant use of network bandwidth that will be incurred if the agent is remote from the database, versus the savings in processing resources on the database host when an agent is not running there.

2.5.1.1 Environment Requirements to Use a Java Agent

Windows, UNIX and Linux, All Supported Databases

A Java environment is required on all platforms. Download and install either the Java Developer Kit (JDK) or the Java Runtime Environment (JRE) from the Oracle website.

DB2

A TCP/IP port must be configured and active.

Oracle

The listener must be configured and running.

SQL Server

A static TCP/IP port must be configured and enabled.

Sybase

Know the ASE listen port.

Teradata

  • Know the host name and port number of the database.
  • Download the appropriate JDBC driver from the database vendor's website before installing the Java agent. You get prompted for the location during the installation steps in this guide.

INFORMIX

A TCP/IP port must be configured and active.

Hive

A TCP/IP port must be configured and active.

ADW/ATP

For more information, see: Connecting Veridata Agent to ADW/ATP.

2.5.2 Oracle GoldenGate Veridata C-Agent

Oracle GoldenGate Veridata also provides a C-code based agent for the following databases:

  • The C-agent is required for NonStop SQL/MP and Enscribe databases running on the NonStop platform. This agent can be installed in a Guardian environment.

  • The C-agent is supported for the Oracle database, but as of release 11.2.1.0.0, it will no longer be enhanced.

  • You must install the C-agent on the same system as the one that hosts the database.

  • For Oracle, a dynamically linked C-agent is available. If you use this agent, you must set the following environment variables:

Environment Variables for Dynamically Linked C-Agents

Variable Operating System

PATH=Oracle_libraries

Windows

SHLIB_PATH=Oracle_libraries

HP-UX

LIBPATH=Oracle_libraries

IBM AIX

LD_LIBRARY_PATH=Oracle_libraries

All other supported UNIX platforms

2.5.3 Disk and Memory Requirements for the Agent Component

  • The agent requires at least 1GB of RAM.

  • The disk space requirements for the Oracle GoldenGate Veridata Agent vary by platform, but up to 200 MB may be required. On UNIX and Linux, additional space might be required to install the Java environment (if not already installed).

  • The main consumers of processing resources are the row sorting operations that are required during a comparison. To improve performance, you might need to increase the temporary memory space in the database if the columns that are being used as keys are not a native unique index or primary key. You specify the columns to use as keys when configuring Oracle GoldenGate Veridata.

  • Using server-side sorting instead of database sorting might reduce the load on the database server and improve comparison performance, depending on the number of rows, the indexes defined, the keys used, and the way the database is tuned. See Disk and Memory Requirements for the Server Component.

2.5.4 Database Privileges for the Agent Component

Oracle GoldenGate Veridata Agent makes use of a database login, which must be created before you can run comparisons. You provide the login and password when you configure connection objects in the Oracle GoldenGate Veridata Web interface. The following are the database privileges that are required for the database user.

Required database privileges for Oracle GoldenGate Veridata Agent

DB2

  • SELECT privileges on the tables that will be compared.

Oracle

  • GRANT CONNECT

  • GRANT SELECT on the tables to be compared. It is recommended, but not necessary, to GRANT SELECT ANY TABLE.

  • SELECT_CATALOG_ROLE

NonStop SQL/MP and Enscribe

  • Read access to the SQL/MP system catalog (for queries to CATALOGS table).

  • Read access to the SQL/MP catalogs that you want Oracle GoldenGate Veridata to use.

  • Read access to the DDL dictionaries that you want Oracle GoldenGate Veridata to use.

  • Read access to the Enscribe and SQL/MP tables that will be compared.

  • Read, write, create, purge permissions for the Oracle GoldenGate Veridata report and trace files, and access to the sub volumes where they are installed.

SQL Server

  • db_datareader or the equivalent on the tables to be compared.

  • VIEW DEFINITION in the databases to be compared.

  • The database must allow SQL Server authentication.

Sybase ASE

  • Access to the databases to be compared.

  • SELECT privileges on the tables to be compared.

  • SELECT privileges on the sysdatabases system table in the master database to view the list of databases available in the server.

Teradata

  • SELECT privileges on the tables to be compared.

Informix

SELECT privileges on the tables to be compared.

BigData Hive

SELECT privileges on the tables to be compared.

Required Database Privileges for Using the Repair Feature

For all databases, the database user must have the UPDATE, INSERT, and DELETE privileges on the tables to be repaired.

For Sybase database, if the table has triggers and suppression of triggers enabled, the database user must have the replication_role privilege.

For SQL Server database, If the table being repaired has 'identity columns', the Repair User specified must be either the table owner, or should have ALTER permission on the table that is being repaired.

2.6 Oracle GoldenGate Veridata Server System Requirements

This section describes the installation location, additional programs, disk, memory, and repository requirements for Oracle GoldenGate Veridata Server.

2.6.1 Location for the Server Component

The server and web user interface components are installed from one installation program on Windows, UNIX, and Linux systems. The installer includes all files that are needed to run those programs. One installation can be used for comparisons among all of the supported databases, but multiple installations can be used as needed.

Do not install the server and web user interface components on a NonStop system. To use Oracle GoldenGate Veridata for NonStop databases:

  • Install the server and web user interface components on a supported Windows, UNIX, or Linux system.

  • Make certain that this system has access over high-speed network connections to the NonStop systems.

2.6.2 Disk and Memory Requirements for the Server Component

The server component uses about 200 MB of fixed virtual memory for basic tasks. The remaining virtual memory is used for comparisons. The main consumers of processing resources on the Oracle GoldenGate Veridata machine are the row sorting operations of the initial comparison step when using server-side sorting.

Enough combined disk space and virtual memory is needed to store all of the rows that are sent for comparison from the source and target systems. To estimate the amount of memory per row:

((number of cols in key + 1) * 4) + 16 + (comparison width of a key col)

Where:

comparison width of a key col depends on the comparison format that is selected by Oracle GoldenGate Veridata (or a user override) to use for a comparison.

Comparison format data sizes:

Comparison Format Data Size

Numbers

One byte for each significant digit. Leading zeros and trailing zeros after the decimal point (such as the right most zeros in 1234.500) are not counted.

Timestamp

19 to 32 bytes depending on the fractional precision.

Date

10 bytes.

Time

8 to 18 bytes depending on the fractional precision.

String

1 to 4 bytes per character for the UTF-8 encoding of the Java agent. The NonStop agent and the Oracle C agent use the database native character set.

Binary

The bytes as stored in the database.

For example, the number 109998877, if compared as a decimal float, would require:

((1 + 1) * 4) + 16 + 9 = 33 bytes of memory for this row

Note:

This assumes that all non-key columns are compared by using a hash, not literally. More space is needed for literal comparisons

Oracle GoldenGate Veridata uses an external merge sort to sort the data. As data is received from the agent, the rows are sorted in memory. When a memory buffer is full, the sorted rows are written to disk.

In order to sort the data, the sort process matches the initial data set size for temporary storage space. The required amount of temporary space is determined by the number of rows, the row size, and the amount of available sort memory. The following cases illustrate the different modes of the sort depending on the available resources.

  • In-Memory Sort: This sorts the data entirely in memory and is the fastest method, but the memory requirements may exceed what is available. The sort memory must be approximately 2.5 times larger than the size of the data set.

  • One Disk Pass: This sorts data and writes to the disk only once. It requires sort disk space equal to the size of the data set. This process is almost as fast as the in-memory sort and the memory requirements are lower. In general the Oracle GoldenGate Veridata server can write the rows to disk faster than the agent can read them from the database.

  • Two Disk Passes: This sorts and writes to the disk twice, requiring sort disk space twice the size of the data set. Although the disk requirement is greater, very large data sets can be sorted with a reasonable amount of memory.

  • Three or More Disk Passes: After all of the rows have been received from the agent, additional sorting may be required before the rows are ready for the final write to disk. If it is necessary to access the disk three or more times, the required sort space will be three or more times the data set size. This is slow and should be avoided.

Beyond this allocation, memory is required for storing rows during the second step of processing, the confirmation step. This can be up to 20 MB if you expect a large number of rows to require confirmation, as is usually the case when replication latency is very high. These rows are staged in the main memory before they are confirmed.

On 64-bit systems, more memory can be addressed, so more data can be stored in main memory instead of on slower disk devices. The memory that is used in the initial comparison step is not necessarily all released at once to be available for the confirmation step. Consequently, some memory will be shared between processes. When the sort cannot hold all of the rows in memory, it uses disk storage.

When deciding how much memory to allocate, be aware of the following ways that you can manage it with parameter settings within the Oracle GoldenGate Veridata application:

  • The temporary space should be located on a reasonably fast file system. A network file system located on a remote server may slow the comparison processing.

  • You can increase disk I/O performance by specifying multiple temporary directories with profile settings. For maximum benefit, put the directories on different physical disks.

  • You can use a profile setting to terminate the confirmation step after a given number of out-of-sync rows, to work around resource limitations.

  • Additional memory properties can be controlled with server parameters. See Oracle GoldenGate Veridata Server Configuration Parameters in Administering Oracle GoldenGate Veridata.

2.6.3 Repository Requirements for the Server Component

Oracle GoldenGate Veridata Server requires a database to serve as a repository for objects that store the information and environment preferences that users create when using Oracle GoldenGate Veridata Web interface.

Use the Repository Creation Utility (RCU) to create the repository. See Creating the Oracle GoldenGate Veridata Repository Schema.

You can use the following databases as a repository:

  • Oracle

  • SQL Server

2.6.3.1 Required Database Privileges for Oracle GoldenGate Veridata Server

Oracle

  1. Create a user and password.

  2. Specify QUOTA UNLIMITED on the user's default tablespace.

SQL Server

  1. Create a database and login that is a user of the database where you will be installing the repository.
  2. Grant this login sufficient privileges to perform the following operations:
    • CONNECT to the database

    • CREATE, ALTER, DROP TABLE in the database

    • CREATE and DROP INDEX in the database

    • INSERT, UPDATE, DELETE from tables in the database

    • SELECT from tables in the database

    • ALTER SCHEMA of the login's default schema

2.6.3.2 Required Environment Components for Oracle GoldenGate Veridata Server

Oracle

  1. The database instance name

  2. The ORACLE_HOME (if using TNSNAMES connection method)

  3. Default and temporary tablespaces for the repository (if you will be creating a new user for the server component during installation)

  4. A login and password, if using an existing database user for the repository.

SQL Server

  1. The SQL Server instance must be configured to use a static port number. This port is stored in a configuration file so that it can be referenced to make JDBC connections to the database.
  2. A login and password (or integrated authentication), if using an existing database user for the repository.

2.7 Oracle GoldenGate Veridata Web User Interface Requirements

This section describes the Java package, browsers, screen resolution, security, and ports recommended or required for the Oracle GoldenGate Web User Interface.

For more information, see Oracle Fusion Middleware System Requirements and Specifications.

2.7.1 Location for the Web Component

See Location for the Server Component. One installer program installs both Oracle GoldenGate Veridata Web Server component and Oracle GoldenGate Veridata Web User Interface.

2.7.2 Java Environment for the Web User Interface

JDK 1.8.0_221 or higher is required for the Veridata Web User Interface installation.

2.7.3 Supported Browsers for the Web User Interface

2.7.4 Recommended Screen Resolution for the Web User Interface

Minimum of 1024 x 768

2.7.5 Port Numbers for the Web User Interface

  • The Oracle GoldenGate Veridata Web application interacts with Oracle WebLogic Server. Oracle WebLogic Server is installed with Oracle GoldenGate Veridata Server on default ports. You can change the port numbers if needed.

  • Oracle GoldenGate Veridata Web makes use of the default port 8830.

2.7.6 Security for the Web User Interface

The web server provides user security roles that control access to certain pages of the Oracle GoldenGate Veridata Web interface. To create users and define user roles, use the Oracle WebLogic Server Administration Console. For more information, see Securing Access to Oracle GoldenGate Veridata by Defining User Roles in Administering Oracle GoldenGate Veridata.

2.8 SQL/MP Data Exclusions

On SQL/MP tables with clustered keys, the right-most portion of the primary key is a timestamp added by the file system. For compare pairs composed of such tables, the timestamp will be different on the source and target systems. As a result, it must be excluded from the comparison, because Oracle GoldenGate Veridata compares keys to ensure that the correct rows are compared.

If, after the timestamp portion of a key is eliminated, the remaining key columns do not produce a unique key value, then those tables must have a unique index or other columns that can be specified to create a unique value. Otherwise, they cannot be compared with Oracle GoldenGate Veridata.