2 Oracle GoldenGate Veridata System Requirements

2.3.1 Oracle GoldenGate Veridata Java agent

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

• DB2 LUW and Z/OS

• Oracle

• SQL Server

• Sybase ASE

• Teradata

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.

2.3.2 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

2.3.3 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 Section 2.4.2, "Disk and Memory Requirements for the Server Component."

2.3.4 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 subvolumes 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.

2.4.1 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.

2.4.2 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:

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

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.

The following table shows memory requirements for some sample data sets.

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.

The sort performs better if all of the data that needs to be sorted during the initial comparison step can be stored in main memory. 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 control the amount of memory that is allocated to each of the processing steps with profile settings.

• 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 Chapter 11, "Oracle GoldenGate Veridata Server Configuration Parameters".

2.4.3 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. You can use the following databases as a repository:

• MySQL

• Oracle

• SQL Server

When installing Oracle GoldenGate Veridata Server, you can have the installer create a database (or schema if using Oracle) for the repository or install the repository objects into an existing database or schema.

The repository can be installed in a database on the same system as the server and web components, or it can be installed on a different system in a multi-tier configuration. For a multi-tier installation, enable communication between hosts as follows:

• To use a MySQL database repository, all required MySQL client software is installed with the server and web components.

• To use an Oracle database repository with Oracle GoldenGate Veridata server and web components installed on a Windows, UNIX, or Linux system, the Oracle client software is installed with the server and web components. Oracle GoldenGate Veridata supports TNSNAMES and EZCONNECT connection naming methods.

  • To use TNSNAMES, the database instance where the repository will be installed must be included in the tnsnames.ora file and in the listener.ora file. Make certain that TNSNAMES is one of the values in the NAMES.DIRECTORY_PATH parameter in the sqlnet.ora file on the database system.

  • To use EZCONNECT, you will need to supply the installation program with the name or IP address of the database server (domain-qualified if required by the operating system), the database listening port number, and the instance name of the database.

• To use a SQL Server database repository with server and web components installed on a different system, make certain that both systems are registered with the DNS.

2.5.1 Location for the Web Component

See Section 2.4.1, "Location for the Server Component". One installer program installs both Oracle GoldenGate VeridataWeb Server component and Oracle GoldenGate Veridata Web User Interface.

2.5.2 Java Environment for the Web User Interface

Except for UNIX and Linux, the installation package includes the required Java Run-time Environment (JRE) 1.6.x, which is installed into the JRE directory within the main Oracle GoldenGate Veridata installation. To ensure that the web client runs properly, do not change this JRE environment.

2.5.3 Supported Browsers for the Web User Interface

• Microsoft Internet Explorer version 6 or higher

• Mozilla Firefox version 1.0.4 and higher

2.5.4 Recommended Screen Resolution for the Web User Interface

Minimum of 1024 x 768

2.5.5 Port Numbers for the Web User Interface

• The Oracle GoldenGate Veridata Web application interacts with the Apache Tomcat web server. Tomcat is installed with Oracle GoldenGate Veridata Server on default ports. You can change the port numbers if needed (see Appendix B, "Changing Oracle GoldenGate Veridata Web Port Numbers").

• Oracle GoldenGate Veridata Web makes use of the following default ports, which you can change during installation:

  • 8820: Shutdown port

  • 8830: HTTP port

  • Other port numbers are used by default. You can change these port numbers after installation by following the directions in Appendix B, "Changing Oracle GoldenGate Veridata Web Port Numbers".

2.5.6 Security for the Web User Interface

The Tomcat web server provides user security roles that control access to certain pages of the Oracle GoldenGate Veridata Web interface. You will be asked to specify an initial Oracle GoldenGate Veridata Administrator user and password during installation. You can use this user to create additional users after installation and assign them to roles.