Prepare

• Supported Databases for Compare

• Supported Databases for Repair

• Supported Databases for Repair SQL

• Supported Datatypes

• Oracle GoldenGate Veridata Agent System Requirements

• Oracle GoldenGate Veridata Server System Requirements

• Oracle GoldenGate Veridata Distribution This topic details how to download the files of Oracle GoldenGate Veridata files and C-Agent.

Supported Databases for Compare

Oracle GoldenGate Veridata supports the following databases for comparisons:

• Apache Hive

• HPE NonStop

• IBM Db2

• MariaDB Server

• Microsoft SQL Server

• MySQL

• Oracle Database

• PostgreSQL

• Snowflake

• Sybase Adaptive Server Enterprise

• Teradata Vantage

• MongoDB

• SingleStore Database

• Databricks

Note: Only NoSQL source to NoSQL target comparisions are supported.

For 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.

Supported Databases for Repair

Oracle GoldenGate Veridata supports the following databases for repair functionality:

• HPE NonStop

• IBM Db2

• MariaDB

• Microsoft SQL Server

• MySQL

• Oracle Database

• PostgreSQL

• Snowflake

• Sybase Adaptive Server Enterprise

• Teradata Vantage

• MongoDB

• SingleStore Database

• Databricks

For 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.

Supported Databases for Repair SQL

Oracle GoldenGate Veridata supports the following target databases for Repair SQL functionality:

• Oracle Database

• Microsoft SQL Server

• Snowflake

• MongoDB

• Databricks

Supported Datatypes

• Supported Datatypes - Oracle

• Supported Datatypes - Microsoft SQL Server

• Supported Datatypes - PostgreSQL

• Supported Datatypes - MySQL, MariaDB

• Supported Datatypes - DB2 LUW

• Supported Datatypes - DB2 for i

• Supported Datatypes - DB2 z/OS

• Supported Datatypes - Sybase Adaptive Server Enterprise

• Supported Datatypes - Teradata Vantage

• Supported Datatypes - Snowflake

• Supported Datatypes - SingleStore Database

• Supported Datatypes - Databricks

• Generic Limitations and Clarifications

Supported Datatypes - Oracle

The Oracle GoldenGate Veridata supports the listed datatypes for the Oracle database:

• BOOLEAN

• CHAR

• NCHAR

• VARCHAR2

• VARCHAR

• NVARCHAR2

• NUMBER

• BLOB

• CLOB

• NCLOB

• LONG

• RAW

• LONG RAW

• ROWID

• BINARY_FLOAT

• BINARY_DOUBLE

• DATE

• TIMESTAMP

• TIMESTAMP WITH TIMEZONE

• TIMESTAMP WITH LOCAL TIME ZONE

• UROWID

• XMLTYPE

• INTERVAL YEAR [(year_precision)] TO MONTH

• INTERVAL DAY [(day_precision)] TO SECOND [(fractional_seconds_precision)]

• FLOAT

• UDTs

• VECTOR

For Oracle Boolean Data Type

• Supported mapping MySQL Data Type using veridata number compare format: Boolean and Number.

• Supported mapping MySQL Data Type using veridata string compare format with limitation: Char andVarchar.

• Limitation: Only uppercase values TRUE and FALSE are treated as in-sync.

• Not supported MySQL Data Type: Binary and Varbinary

Limitations and Clarifications:

Both Object types and Collection types UDTs are supported

Supported Datatypes - Microsoft SQL Server

The Oracle GoldenGate Veridata supports the listed datatypes for the SQL Server database:

• BIGINT

• BIT

• INT

• SMALLINT

• TINYINT

• DECIMAL

• MONEY

• SMALLMONEY

• NUMERIC

• FLOAT

• REAL

• CHAR

• NCHAR

• VARCHAR

• NVARCHAR

• TEXT

• NTEXT

• BINARY

• VARBINARY

• IMAGE

• DATE

• DATETIME

• DATETIME2

• SMALLDATETIME

• DATTIMEOFFSET

• TIME

• GEOGRAPHY

• GEOMETRY

• UNIQUEIDENTIFIER

• XML

For more information about conversion of SQL Server data types to Oracle data types, see Data Type Conversion in Database Gateway for SQL Server User’s Guide.

Supported Datatypes - PostgreSQL

The Oracle GoldenGate Veridata supports the listed datatypes for PostgreSQL:

• Bit(n)

• Bit Varying(n)

• Boolean

• Char

• citext

• Varchar(n)

• Time with/without timezone

• Date

• Interval

• Bigint

• Serial

• Smallserial

• Bigserial

• Numeric

• Decimal

• Money

• Real

• Double precision

• cidr

• inet

• macaddr

• macaddr8

• uuid

• text

• bytea (binary)

• xml

• smallint

• integer

• json

• jsonb

Non-Supported PostgreSQL Data Types

• arrays

• box

• circle

• composite types

• line

• lseq

• object identifiers

• OID

• pg_lsn

• pseduo types

• Point

• path

• polygon

• range types

• tsvector

• tsquery

• enum

• domain

For Postgres BIT Varying Data Type

• Supported mapping Oracle/MySQL Data Type using veridata string compare format: Char and Varchar

• Not supported Oracle/MySQL Data Type: Binary, Varbinary, and Number

Limitations of Support

• Bit(n)/Bit Varying(n):

  • Heterogeneous: As the source side, Bit(n)/Bit Varying(n) can only be mapped with a character type of the non-PostgreSQL target database. This is because, the leading “0” of the source data gets truncated in the target db during repair, for example, the target is a number type.

  • Homogeneous: None.

• Network datatype (inet,cidr,uuid):

  • Heterogeneous: All string datatypes like char/nchar/varchar in source side and network datatypes like inet/cidr/uuid in PostgreSQL target side can only considered as hash column.

  • Homogeneous: None.

• MAC/MAC8 datatype:

  • Heterogeneous: All string datatypes like char/nchar/varchar in source side and datatypes like mac/mac8 in PostgreSQL target side, while repair operation, it is successful but it always save in the one formatxx:xx:xx:xx:xx:xx even though the allowed format is multiple, that is xxx:xxx:xxx:xxx or xx-xx-xx-xx-xx-xx. Therefore, it always shows the OOS after repair whenever there is a different format from source side.

  • Homogeneous: None.

• JSONB datatype:

  • Heterogeneous: All string datatypes like char/nchar/varchar in source side and jsonb in PostgreSQL target side, after repair the order of json key/values are not stored in original order. Therefore, it will be OOS for next compare pair run.

  • Homogeneous: None.

• Timestamp with timezone:

  • Heterogeneous: PostgreSQL is not storing the timezone value in the database. Whenever a timestamp with timezone value is inserted, PostgreSQL converts the timestamp into UTC and inserts into it. While retrieving, the actual timezone is not known. Comparing it with the DBs like oracle, sqlserver which stores complete timestamp along with timezone result in OOS all the time.

• Time/Time with Timezone:

  • Homogeneous: PostgreSQL- PostgreSQL Time/Time with Timezone datatype comparison and repair has inconsistencies when the time column is primary key. Some of the rows may not be picked for compare and repair.

• Real:

  • Heterogeneous: Oracle GoldenGate for Veridata cannot support the compare pair of FLOAT (Oracle) to REAL (PostgreSQL). Some data is always OOS after repair due to the internal representation of the data type in db. Substitute pairs are binary float (Oracle) to real (PostgreSQL) and float (Oracle) to numeric (PostgreSQL).

  • Real does not store the value as exact number in database. For example, 0.8 is stored as 0.800000011920929. On compare it always shows extra values, but it does not impact the repair functionality.

• Interval:

  • Heterogeneous: During repair Veridata may insert/update 00 to column. Oracle GoldenGate Veridata currently uses CAST (? AS INTERVAL) as part of its insert and update queries. This cast defaults to INTERVAL SECOND. Therefore, when values like ‘05’, ‘57’, or ‘98’ are used as cast, they result in values, such as:

    • 5 –> 00:00:05

    • 57 –> 00:00:57

    • 98 –> 00:01:38

    Therefore, if these values are inserted/updated to a column with INTERVAL HOUR, the result is 00. The same is for other type of INTERVAL.

• citext

  Repair function is not fully supported when citext is mapped to a string-like data type on either source or target side. When citext is on source side,following change is needed for repair to work: go to Profile Configuration > Edit Existing Profile > Repair, and unselect the Check Changed Values setting.

Supported Datatypes - MySQL, MariaDB

The Oracle GoldenGate Veridata supports the listed datatypes for the MySQL, MariaDB databases:

• BIGINT

• BINARY

• BIT

• BLOB

• CHAR

• DATE

• DATETIME

• DECIMAL

• DOUBLE

• ENUM

• FLOAT

• INT

• INTEGER

• LONGBLOB

• LONGTEXT

• MEDIUMBLOB

• MEDIUMINT

• NUMERIC

• REAL

• SET

• SMALLINT

• TEXT

• TIME

• TIMESTAMP

• TINYBLOB

• TINYINT

• TINYTEXT

• VARCHAR

• VARBINARY

• YEAR

For MySQL BIT Data Type

• Supported mapping Oracle/Postgres Data Type using veridata number compare format: Number

• Supported mapping Oracle Data Type using veridata string compare format with limitation: Char and Varchar.

• Limitation: not applicable to compare value with leading 0, such as 0001101

• Supported mapping Postgres Type using veridata string compare format with limitation: Char, Varchar and Bit varying

• Limitation: not applicable to compare value with leading 0, like 0001101

• Not supported Oracle Data Type: Binary and Varbinary

Limitations and Clarifications

• For Oracle GoldenGate Veridata repair to properly throw errors when invalid or missing values are detected, user should set SQL Mode to “strict”. This can be set on global level when MySQL starts, or session level via connection string in agent.properties, for example: database.url=jdbc:mysql://host:3306?sessionVariables=sql_mode=(select concat(@@SESSION.sql_mode,',STRICT_TRANS_TABLES'))

• When using REAL as primary key, MySQL client and Veridata may not able to retrieve certain rows (for example, WHERE `PKCOL` = '-99.9999'), Oracle GoldenGate Veridata skips these rows during compare and repair.

• When using nonstandard FLOAT(M,D) and DOUBLE(M,D), the (M,D) in DDL need to match the actual precision and scale stored, and both Source and Target need to be MySQL.

Supported Datatypes - DB2 LUW

The Oracle GoldenGate Veridata supports the listed datatypes for the DB2 LUW database:

• BIGINT

• BLOB

• CHAR

• CHAR FOR BIT DATA

• CLOB

• DATE

• DBCLOB

• DECFLOAT

• DECIMAL

• DOUBLE

• FLOAT

• GRAPHIC

• INTEGER

• LONG VARCHAR

• LONG VARCHAR FOR BIT DATA

• LONG VARGRAPHIC

• NUMERIC

• REAL

• SMALLINT

• TIME

• TIMESTAMP

• VARCHAR

• VARCHAR FOR BIT DATA

• VARGRAPHIC

• XML

Supported Datatypes - DB2 for i

The Oracle GoldenGate Veridata supports the listed datatypes for DB2 for i:

• BIGINT

• BLOB

• CHAR

• CHAR FOR BIT DATA

• CLOB

• DATE

• DBCLOB

• DECFLOAT

• DECIMAL

• DOUBLE

• FLOAT

• GRAPHIC

• INTEGER

• LONG VARCHAR

• LONG VARCHAR FOR BIT DATA

• LONG VARGRAPHIC

• NUMERIC

• REAL

• ROWID

• SMALLINT

• TIME

• TIMESTAMP

• VARCHAR

• VARCHAR FOR BIT DATA

• VARGRAPHIC

• XML

Limitations and Clarifications

• The decimal part of REAL value from the wldb2 jdbc driver always store in the 16 digits precision, for example, 0.8 converts 0.800000011920929 and compare will always fail if the decimal values are present.

Supported Datatypes - DB2 z/OS

The Oracle GoldenGate Veridata supports the listed datatypes for the DB2 z/OS database:

• BIGINT

• BINARY

• BLOB

• CHAR

• CHAR FOR BIT DATA

• CLOB

• DATE

• DBCLOB

• DECFLOAT

• DECIMAL

• DOUBLE

• FLOAT

• GRAPHIC

• INTEGER

• LONG VARCHAR

• LONG VARCHAR FOR BIT DATA

• LONG VARGRAPHIC

• NUMERIC

• REAL

• ROWID

• SMALLINT

• TIME

• TIMESTAMP

• TIMESTAMP WITH TIME ZONE

• VARBINARY

• VARCHAR

• VARCHAR FOR BIT DATA

• VARGRAPHIC

• XML

Supported Datatypes - Sybase Adaptive Server Enterprise

The Oracle GoldenGate Veridata supports the listed datatypes for the Sybase database:

• bigdatetime

• bigint

• bigtime

• binary

• bit

• char

• date

• datetime

• decimal

• float

• image

• int

• money

• numeric

• real

• smalldatetime

• smallint

• smallmoney

• sysname

• text

• time

• timestamp

• tinyint

• unichar

• unitext

• univarchar

• unsigned bigint

• unsigned int

• unsigned smallint

• varbinary

• varchar

Supported Datatypes - Teradata Vantage

The Oracle GoldenGate Veridata supports the listed datatypes for the Teradata database:

• ARRAY

• BIGINT

• BLOB

• BYTE

• BYTEINT

• CHAR

• CLOB

• DATE

• DECIMAL

• DISTINCT

• FLOAT

• GRAPHIC

• INTEGER

• INTERVAL DAY

• INTERVAL DAY TO HOUR

• INTERVAL DAY TO MINUTE

• INTERVAL DAY TO SECOND

• INTERVAL HOUR

• INTERVAL HOUR TO MINUTE

• INTERVAL HOUR TO SECOND

• INTERVAL MINUTE

• INTERVAL MINUTE TO SECOND

• INTERVAL MONTH

• INTERVAL SECOND

• INTERVAL YEAR

• INTERVAL YEAR TO MONTH

• LONG VARCHAR

• LONG VARGRAPHIC

• NUMBER

• SMALLINT

• STRUCT

• TIME

• TIME WITH TIME ZONE

• TIMESTAMP

• TIMESTAMP WITH TIME ZONE

• VARBYTE

• VARCHAR

• VARGRAPHIC

Supported Datatypes - Snowflake

The Oracle GoldenGate Veridata supports the listed datatypes for the Snowflake database:

• BIGINT

• BINARY

• BOOLEAN

• BYTEINT

• CHAR

• CHAR VARYING

• CHARACTER

• DATE

• DATETIME

• DECIMAL

• DOUBLE

• DOUBLE PRECISION

• FLOAT

• FLOAT4

• FLOAT8

• INT,

• INTEGER

• NCHAR

• NCHAR VARYING

• NUMBER

• NUMERIC

• NVARCHAR

• NVARCHAR2

• REAL

• SMALLINT

• STRING

• TEXT

• TIME

• TIMESTAMP

• TIMESTAMP_LTZ

• TIMESTAMP_NTZ

• TIMESTAMP_TZ

• TINYINT

• VARBINARY

• VARCHAR

• VARIANT

• VECTOR

Non-Supported Snowflake Data Types

• ARRAY

• OBJECT

• GEOGRAPHY

• GEOMETRY

Supported Datatypes - SingleStore Database

The Oracle GoldenGate Veridata supports the listed datatypes for the SingleStore database:

• BIGINT

• BINARY

• BIT

• BLOB

• CHAR

• DATE

• DATETIME

• DECIMAL

• DOUBLE

• ENUM

• FLOAT

• INT

• INTEGER

• LONGBLOB

• LONGTEXT

• MEDIUMBLOB

• MEDIUMINT

• NUMERIC

• REAL

• SET

• SMALLINT

• TEXT

• TIME

• TIMESTAMP

• TINYBLOB

• TINYINT

• TINYTEXT

• VARCHAR

• VARBINARY

• YEAR

Supported Datatypes - Databricks

The Oracle GoldenGate Veridata supports the listed datatypes for Databricks:

• ARRAY

• BIGINT

• BINARY

• BOOLEAN

• DATE

• DECIMAL

• DOUBLE

• FLOAT

• INT

• MAP

• SMALLINT

• STRING

• STRUCT

• TIMESTAMP

• TINYINT

Generic Limitations and Clarifications

This topic lists a few generic limitations and clarifications:

• As the floating-point data types are approximate values by definition, Oracle GoldenGate Veridata UI may display slightly different values than expected (for example, extra decimal values)

• For database with TIME data type that supports value outside range of 00:00:00 to 23:59.59, the compare will only work when Source and Target are the same database.

• Whenever there is a precision for any datatype, such as REAL/FLOAT or Double on the database side, Oracle GoldenGate Veridata rounds off the lower precision present either on the source or the target database. Veridata considers the lower precision of data during comparison phase.

• Oracle GoldenGate Veridata internally converts decimal numbers with a large scale by truncating tail digits. The limitations applies to all databases except Oracle. This is because Oracle GoldenGate Veridata utilizes a template to mask decimal numbers, which, in cases of a large scale, leaves few digits for representing the scale part. For example, a number like 6.710123456789e-26, with a scale of 38 digits, would be truncated by Oracle GoldenGate Veridata to retain the first 15 digits, converting it to 0. For scenarios where preserving all digits of the scale is crucial, Oracle recommends using the string or other compare formats instead of the number compare format when configuring the compare pair.

• Oracle Veridata currently does not support or properly handle scenarios in which duplicate rows are present in the tables of a Compare Pair (CP). When duplicate records exist in either the source or target datasets, Veridata may produce inaccurate comparison results, fail to detect differences correctly.

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. This topic contains the following:

• Disk and Memory Requirements for the Agent Component

• Database Privileges for the Agent Component

Disk and Memory Requirements for the Agent Component

• The agent requires at least 1GB of RAM.

  For more information on agent memory requirement, see Agent Memory.

• 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

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

IBM Db2

• SELECT privileges on the tables that will be compared.

Oracle Database

• GRANT CONNECT

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

• SELECT_CATALOG_ROLE

• EXECUTE_CATALOG_ROLE (for GET_TAG and SET_TAG procedures)

• CREATE TABLE (for COOS Join in case of tables with no primary/unique constraint)

• CREATE TABLESPACE (for COOS Join in case of tables with no primary/unique constraint)

• GRANT UPDATE, DELETE, INSERT (for COOS Join in case of tables with no primary/unique constraint)

HPE NonStop

• 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.

Microsoft SQL Server

• db_datareaderor the equivalent on the tables to be compared.

• VIEW DEFINITION in the databases to be compared.

• The database must allow SQL Server authentication.

Sybase Adaptive Server Enterprise

• 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 Vantage

• SELECT privileges on the tables to be compared.

Apache 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.

Oracle GoldenGate Veridata Server System Requirements

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

Oracle GoldenGate Veridata server is designed to run on a dedicated Linux host only. Ensure to stop all other applications and remove any MySQL instances before server install to avoid port conflicts.

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. See GoldenGate Certifications.

• Location for the Server Component

• Disk and Memory Requirements for the Server Component

Location for the Server Component

The server and web user interface components are installed from one installation program on 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 Linux system.

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

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 uses 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 = 33bytes 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 Server Parameters.

Oracle GoldenGate Veridata Distribution

This topic details how to download the files of Oracle GoldenGate Veridata files and C-Agent.

• Downloading Oracle GoldenGate Veridata

• Downloading Oracle GoldenGate Veridata C-Agent and Java Agent

Downloading Oracle GoldenGate Veridata

A distribution is an archive file containing an installer; when you run the installer, the set of Oracle GoldenGate Veridata components and feature that are included with the distribution are installed. You will need a certified JDK on your system in order to be able to run the installer. For more information, see Prerequistes in Installing and Running Oracle GoldenGate Veridata

You can download Oracle GoldenGate Veridata from the Oracle GoldenGate Downloads page at https://www.oracle.com/middleware/technologies/goldengate-downloads.html and from the Oracle Software Delivery Cloud site, at https://edelivery.oracle.com/osdc/faces/SoftwareDelivery.

The following table describes the products and feature sets in Oracle GoldenGate Veridata.

Table 1 Oracle GoldenGate Veridata Product

Product	Feature Set	Description
Oracle GoldenGate Veridata	Veridata Server	The Veridata Server component includes the web server, the web application, and command-line utilities such as vericom .
	Veridata Agent	This component installs only the Veridata Agent.
Internal Features	OPatch	The OPatch utility is a tool that allows the application and rollback of interim patches to Oracle products.

Downloading Oracle GoldenGate Veridata C-Agent and Java Agent

Oracle GoldenGate Veridata C-Agent and the Java Agent platforms are available for download on Oracle Technology Network Oracle GoldenGate Downloads page at: http://www.oracle.com/technetwork/middleware/goldengate/downloads/index.html