Privileges for Netezza Connecting to Netezza as a source Configuring ongoing data replication Netezza to Amazon Redshift conversion settings Netezza to Amazon Redshift conversion optimization settings

Using Netezza as a source for AWS SCT

You can use AWS SCT to convert schemas, code objects, and application code from Netezza to Amazon Redshift.

Privileges for Netezza as a source

The following privileges are required for using Netezza as a source:

select on system.definition_schema.system view
select on system.definition_schema.system table
select on system.definition_schema.management table
list on <database_name>
list on <schema_name>
list on <database_name>.all.table
list on <database_name>.all.external table
list on <database_name>.all.view
list on <database_name>.all.materialized view
list on <database_name>.all.procedure
list on <database_name>.all.sequence
list on <database_name>.all.function
list on <database_name>.all.aggregate

In the preceding example, replace placeholders as following:

Replace database_name with the name of the source database.
Replace schema_name with the name of the source schema.

AWS SCT requires access to the following system tables and views. You can grant access to these objects instead of granting access to system.definition_schema.system view and system.definition_schema.system tables in the preceding list.

select on system.definition_schema._t_aggregate
select on system.definition_schema._t_class
select on system.definition_schema._t_constraint
select on system.definition_schema._t_const_relattr
select on system.definition_schema._t_database
select on system.definition_schema._t_grpobj_priv
select on system.definition_schema._t_grpusr
select on system.definition_schema._t_hist_config
select on system.definition_schema._t_object
select on system.definition_schema._t_object_classes
select on system.definition_schema._t_proc
select on system.definition_schema._t_type
select on system.definition_schema._t_user
select on system.definition_schema._t_usrobj_priv
select on system.definition_schema._vt_sequence
select on system.definition_schema._v_aggregate
select on system.definition_schema._v_constraint_depends
select on system.definition_schema._v_database
select on system.definition_schema._v_datatype
select on system.definition_schema._v_dslice
select on system.definition_schema._v_function
select on system.definition_schema._v_group
select on system.definition_schema._v_obj_relation
select on system.definition_schema._v_obj_relation_xdb
select on system.definition_schema._v_procedure
select on system.definition_schema._v_relation_column
select on system.definition_schema._v_relation_keydata
select on system.definition_schema._v_relobjclasses
select on system.definition_schema._v_schema_xdb
select on system.definition_schema._v_sequence
select on system.definition_schema._v_synonym
select on system.definition_schema._v_system_info
select on system.definition_schema._v_sys_constraint
select on system.definition_schema._v_sys_object_dslice_info
select on system.definition_schema._v_sys_user
select on system.definition_schema._v_table
select on system.definition_schema._v_table_constraint
select on system.definition_schema._v_table_dist_map
select on system.definition_schema._v_table_organize_column
select on system.definition_schema._v_table_storage_stat
select on system.definition_schema._v_user
select on system.definition_schema._v_view
select on system.information_schema._v_relation_column
select on system.information_schema._v_table
select on $hist_column_access_*

Connecting to Netezza as a source

Use the following procedure to connect to your Netezza source database with the AWS Schema Conversion Tool.

To connect to a Netezza source database

In the AWS Schema Conversion Tool, choose Add source.
Choose Netezza, then choose Next.

The Add source dialog box appears.
For Connection name, enter a name for your database. AWS SCT displays this name in the tree in the left panel.

Use database credentials from AWS Secrets Manager or enter them manually:

To use database credentials from Secrets Manager, use the following instructions:
1. For AWS Secret, choose the name of the secret.
2. Choose Populate to automatically fill in all values in the database connection dialog box from Secrets Manager.
For information about using database credentials from Secrets Manager, see Using AWS Secrets Manager.

To enter the Netezza source database connection information manually, use the following instructions:

Parameter	Action
Server name	Enter the Domain Name System (DNS) name or IP address of your source database server.
Server port	Enter the port used to connect to your source database server.
User name and Password	Enter the database credentials to connect to your source database server. AWS SCT uses the password to connect to your source database only when you choose to connect to your database in a project. To guard against exposing the password for your source database, AWS SCT doesn't store the password by default. If you close your AWS SCT project and reopen it, you are prompted for the password to connect to your source database as needed.
Store password	AWS SCT creates a secure vault to store SSL certificates and database passwords. By turning this option on, you can store the database password and connect quickly to the database without having to enter the password.
Netezza driver path	Enter the path to the driver to use to connect to the source database. For more information, see Downloading the required database drivers. If you store the driver path in the global project settings, the driver path doesn't appear on the connection dialog box. For more information, see Storing driver paths in the global settings.

Choose Test Connection to verify that AWS SCT can connect to your source database.
Choose Connect to connect to your source database.

Configuring ongoing data replication

After you convert your Netezza database schemas and apply them to your Amazon Redshift database, you can migrate data with AWS SCT data extraction agents. The agent extracts your data and uploads it to your Amazon S3 bucket. You can then use AWS SCT to copy the data from Amazon S3 to Amazon Redshift.

If data in your source database changes during the migration process, you can capture ongoing changes with your AWS SCT data extraction agents. Then you can replicate these ongoing changes in your target database after you complete the initial data migration. This process is called ongoing data replication or change data capture (CDC).

To configure ongoing data replication for migrations from Netezza to Amazon Redshift

In your source database, create a history database. You can use the following code example in the Netezza command line interface (CLI).
```
nzhistcreatedb -d history_database_name -t query -v 1 -u load_user -o histdb_owner -p your_password
```
In the preceding example, replace history_database_name with the name of your history database. Next, replace load_user with the name of the user that you have defined to load history data to the database. Then, replace histdb_owner with the name of the user that you have defined as the owner of the history database. Make sure that you have already created this user and granted the CREATE DATABASE permission. Finally, replace your_password with a secure password.
Configure the history logging. To do so, use the following code example.
```
CREATE HISTORY CONFIGURATION history_configuration_name HISTTYPE QUERY
    DATABASE history_database_name USER load_user PASSWORD your_password COLLECT PLAN, COLUMN
    LOADINTERVAL 1 LOADMINTHRESHOLD 0 LOADMAXTHRESHOLD 0 STORAGELIMIT 25
    LOADRETRY 2 VERSION 1;
```
In the preceding example, replace history_configuration_name and history_database_name with the names of your history configuration and your history database. Next, replace load_user with the name of the user that you have defined to load history data to the database. Then, replace your_password with a secure password.
Grant read permissions for all tables in the history database. You can use the following code example to grant the SELECT permission.
```
GRANT SELECT ON history_database_name.ALL.TABLE TO your_user;
```
In the preceding example, replace history_database_name with the name of your history database. Next, replace your_user with the name of the user with minimal permissions to work with your Netezza database. You use the credentials of this database user in AWS SCT.
Collect statistics for each table in your source schema to get the information about the cardinality of columns. You can use the following command to generate statistics in your history database.
```
GENERATE STATISTICS on "schema_name"."table_name";
```
In the preceding example, replace schema_name and table_name with the name of your database schema and table.
Make sure that you completed the prerequisites by running the following query:
```
SELECT COUNT(*) FROM history_database_name.history_schema_name."$hist_column_access_N";
```
In the preceding example, replace history_database_name and history_schema_name with the name of your history database and schema. Next, replace N with the the version number of your history database. For more information about history database versions, see the IBM Netezza Documentation.
Install your data extraction agents. For more information, see Installing extraction agents.

Make sure that the {working.folder} parameter in the settings.properties file for all extractor instances points to the same folder. In this case, your extractors can coordinate the CDC session and use a single transaction point for all subtasks.
Register your data extraction agent. For more information, see Registering extraction agents with the AWS Schema Conversion Tool.
Create your CDC task. For more information, see Creating, running, and monitoring an AWS SCT task.
1. Open your project in AWS SCT. In the left pane, choose your source table. Open the context (right-click) menu, and choose Create local task.
2. For Task name, enter a descriptive name for your data migration task.
3. For Migration mode, choose Extract, upload, and copy.
4. Select Enable CDC.
5. Choose the CDC settings tab and define the scope and the schedule of CDC sessions.
6. Choose Test task to verify that you can connect to your working folder, Amazon S3 bucket, and Amazon Redshift data warehouse.
7. Choose Create to create your task.
8. Choose the Tasks tab, choose your task from the list, and choose Start.
The AWS SCT task maintains transactional consistency on the target database. The data extraction agent replicates transactions from the source in transaction ID order.

If you stop any of the migration sessions or if it fails, then the CDC processing also stops.

Netezza to Amazon Redshift conversion settings

To edit Netezza to Amazon Redshift conversion settings, choose Settings in AWS SCT, and then choose Conversion settings. From the upper list, choose Netezza, and then choose Netezza – Amazon Redshift. AWS SCT displays all available settings for Netezza to Amazon Redshift conversion.

Netezza to Amazon Redshift conversion settings in AWS SCT include options for the following:

To limit the number of comments with action items in the converted code.

For Add comments in the converted code for the action items of selected severity and higher, choose the severity of action items. AWS SCT adds comments in the converted code for action items of the selected severity and higher.

For example, to minimize the number of comments in your converted code, choose Errors only. To include comments for all action items in your converted code, choose All messages.
To set the maximum number of tables that AWS SCT can apply to your target Amazon Redshift cluster.

For The maximum number of tables for the target Amazon Redshift cluster, choose the number of tables that AWS SCT can apply to your Amazon Redshift cluster.

Amazon Redshift has quotas that limit the use tables for different cluster node types. If you choose Auto, AWS SCT determines the number of tables to apply to your target Amazon Redshift cluster depending on the node type. Optionally, choose the value manually. For more information, see Quotas and limits in Amazon Redshift in the Amazon Redshift Management Guide.

AWS SCT converts all your source tables, even if this is more than your Amazon Redshift cluster can store. AWS SCT stores the converted code in your project and doesn't apply it to the target database. If you reach the Amazon Redshift cluster quota for the tables when you apply the converted code, then AWS SCT displays a warning message. Also, AWS SCT applies tables to your target Amazon Redshift cluster until the number of tables reaches the limit.
To apply compression to Amazon Redshift table columns. To do so, select Use compression encoding.

AWS SCT assigns compression encoding to columns automatically using the default Amazon Redshift algorithm. For more information, see Compression encodings in the Amazon Redshift Database Developer Guide.

By default, Amazon Redshift doesn't apply compression to columns that are defined as sort and distribution keys. You can change this behavior and apply compression to these columns. To do so, select Use compression encoding for KEY columns. You can select this option only when you select the Use compression encoding option.

Netezza to Amazon Redshift conversion optimization settings

To edit Netezza to Amazon Redshift conversion optimization settings, choose Settings in AWS SCT, and then choose Conversion settings. From the upper list, choose Netezza, and then choose Netezza – Amazon Redshift. In the left pane, choose Optimization strategies. AWS SCT displays conversion optimization settings for Netezza to Amazon Redshift conversion.

Netezza to Amazon Redshift conversion optimization settings in AWS SCT include options for the following:

To work with automatic table optimization. To do so, select Use Amazon Redshift automatic table tuning.

Automatic table optimization is a self-tuning process in Amazon Redshift that automatically optimizes the design of tables. For more information, see Working with automatic table optimization in the Amazon Redshift Database Developer Guide.

To rely only on the automatic table optimization, choose None for Initial key selection strategy.
To choose sort and distribution keys using your strategy.

You can choose sort and distribution keys using Amazon Redshift metadata, statistical information, or both these options. For Initial key selection strategy on the Optimization strategies tab, choose one of the following options:
- Use metadata, ignore statistical information
- Ignore metadata, use statistical information
- Use metadata and statistical information
Depending on the option that you choose, you can select optimization strategies. Then, for each strategy, enter the value (0–100). These values define the weight of each strategy. Using these weight values, AWS SCT defines how each rule influences on the choice of distribution and sort keys. The default values are based on the AWS migration best practices.

You can define the size of small tables for the Find small tables strategy. For Min table row count and Max table row count, enter the minimum and maximum number of rows in a table to define it as a small table. AWS SCT applies the ALL distribution style to small tables. In this case, a copy of the entire table is distributed to every node.
To configure strategy details.

In addition to defining the weight for each optimization strategy, you can configure the optimization settings. To do so, choose Conversion optimization.
- For Sort key columns limit, enter the maximum number of columns in the sort key.
- For Skewed threshold value, enter the percentage (0–100) of a skewed value for a column. AWS SCT excludes columns with the skew value greater than the threshold from the list of candidates for the distribution key. AWS SCT defines the skewed value for a column as the percentage ratio of the number of occurrences of the most common value to the total number of records.
- For Top N queries from the query history table, enter the number (1–100) of the most frequently used queries to analyze.
- For Select statistics user, choose the database user for which you want to analyze the query statistics.
Also, on the Optimization strategies tab, you can define the size of small tables for the Find small tables strategy. For Min table row count and Max table row count, enter the minimum and maximum number of rows in a table to consider it as a small table. AWS SCT applies the ALL distribution style to small tables. In this case, a copy of the entire table is distributed to every node.

Warning Javascript is disabled or is unavailable in your browser.

To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.

Document Conventions

Using Greenplum Database as a source

Using Oracle Data Warehouse as a source