Oracle assessments

This section describes individual premigration assessments for migration tasks that use an Oracle source endpoint.

grant select on gv_$parameter to dms_user;
grant select on v_$instance to dms_user;
grant select on v_$version to dms_user;
grant select on gv_$ASM_DISKGROUP to dms_user;
grant select on gv_$database to dms_user;
grant select on DBA_DB_LINKS to to dms_user;
grant select on gv_$log_History to dms_user;
grant select on gv_$log to dms_user;
grant select on dba_types to dms_user;
grant select on dba_users to dms_user;
grant select on dba_directories to dms_user;
grant execute on SYS.DBMS_XMLGEN to dms_user;

Validate that limited LOB mode only is used when BatchApplyEnabled is enabled

API key: oracle-batch-apply-lob-mode

This premigration assessment validates whether tables in the DMS task includes LOB columns. If LOB columns are included in the scope of the task, you must use BatchApplyEnabled together with limited LOB mode only.

For more information, see Target metadata task settings.

Validate if tables on the source has columns without scale specified for the Number data type

API key: oracle-number-columns-without-scale

This premigration assessment validates whether the DMS task includes columns of NUMBER data type without scale specified. We recommend that you set the endpoint setting NumberDataTypeScale to the value specified in the assessment report.

For more information, see Endpoint settings when using Oracle as a source for AWS DMS.

Validate triggers on the target database

API key: oracle-target-triggers-are-enabled

This premigration assessment validates whether triggers are enabled on the target database. The assessment will fail if triggers are enabled. We recommend that you disable or remove the triggers during the migration.

For more information, see For more information, see DMS best practices.

Validate if source has archivelog DEST_ID set to 0

API key: oracle-zero-archive-log-dest-id

This premigration assessment validates whether endpoint extra connection attribute useZeroDestid=true is set for source if archived log DEST_ID is set to 0.

For more information, see How to handle AWS DMS replication when used with Oracle database in fail-over scenarios.

Validate if secondary indexes are enabled on the target database during full-load

API key: oracle-check-secondary-indexes

This premigration assessment validates whether secondary indexes are enabled during a full-load on the target database. We recommend that you disable or remove the secondary indexes during full-load.

For more information, Best practices for AWS Database Migration Service.

Validate if tables used in the DMS task scope with BatchApplyEnabled have more than 999 columns

API key: oracle-batch-apply-lob-999

Tables with batch optimized apply mode enabled can't have more than a total of 999 columns. Tables that have more than 999 columns will cause AWS DMS to process the batch one by one, which increases latency. DMS uses the formula 2 * columns_in_original_table + columns_in_primary_key <= 999 to calculate the total number of columns per table supported in batch-optimized apply mode.

For more information, see Limitations on Oracle as a target for AWS Database Migration Service.

Check supplemental logging on database level

API key: oracle-supplemental-db-level

This premigration assessment validates if minimum supplemental logging is enabled at the database level. You must enable supplemental logging to use an Oracle database as a source for migration.

To enable supplemental logging, use the following query:

ALTER DATABASE ADD SUPPLEMENTAL LOG DATA

For more information, see Setting up supplemental logging.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

Validate if required DB link is created for Standby

API key: oracle-validate-standby-dblink

This premigration assessment validates if Dblink is created for the Oracle standby database source. AWSDMS_DBLINK is a prerequisite for using a standby database as a source. When using Oracle Standby as a source, AWS DMS does not validate open transactions by default.

For more information, see Working with a self-managed Oracle database as a source for AWS DMS.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

Oracle validation for LOB datatype and if binary reader is configured

API key: oracle-binary-lob-source-validation

This premigration assessment validates if Oracle LogMiner is used for an Oracle database endpoint version 12c or later. AWS DMS does not support Oracle LogMiner for migrations of LOB columns from Oracle databases version 12c. This assessment also checks for the presence of LOB columns and provides appropriate recommendations.

To configure your migration to not use Oracle LogMiner, add the following configuration to your source endpoint:

useLogMinerReader=N;useBfile=Y;

For more information, see Using Oracle LogMiner or AWS DMS Binary Reader for CDC.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

Validate if the database is CDB

API key: oracle-validate-cdb

This premigration assessment validates if the database is a container database. AWS DMS doesn't support the multi-tenant container root database (CDB$ROOT).

For more information, see Limitations on using Oracle as a source for AWS DMS.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

Check the Oracle Database Edition

API key: oracle-check-cdc-support-express-edition

This premigration assessment validates if the Oracle source database is Express Edition. AWS DMS doesn't support CDC for Oracle Express Edition (Oracle Database XE) version 18.0 and later.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

Validate Oracle CDC method for DMS

API key: oracle-recommendation-cdc-method

This premigration assessment validates redo log generation for the last seven days, and makes a recommendation whether to use AWS DMS Binary Reader or Oracle LogMiner for CDC.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

For more information about deciding which CDC method to use, see Using Oracle LogMiner or AWS DMS Binary Reader for CDC.

Validate Oracle RAC configuration for DMS

API key: oracle-check-rac

This premigration assessment validates if the oracle database is a Real Application Cluster. Real Application Cluster databases must be configured correctly. If the database is based on RAC, we recommend that you use AWS DMS Binary Reader for CDC rather than Oracle LogMiner.

This assessment is only valid for a full-load and CDC migration, or a CDC-only migration. This assessment is not valid for a full-load only migration.

For more information, see Using Oracle LogMiner or AWS DMS Binary Reader for CDC.

Validate if DMS user has permissions on target

API key: oracle-validate-permissions-on-target

This premigration assessment validates whether DMS users have all the required permissions on the target database.

Validate if supplemental logging is required for all columns

API key: oracle-validate-supplemental-logging-all-columns

This premigration assessment validates, for the tables mentioned in the task scope, whether supplemental logging has been added to all columns of tables without a primary or unique key. Without supplemental logging on all columns for a table lacking a primary or unique key, the before-and-after image of the data won't be available in the redo logs. DMS requires supplemental logging for tables without a primary or unique key to generate DML statements.

Validate if supplemental logging is enabled on tables with Primary or Unique keys

API key: oracle-validate-supplemental-logging-for-pk

This premigration assessment validates whether supplemental logging is enabled for tables with a primary key or unique index and also checks if AddSupplementalLogging is enabled at the endpoint level. To ensure DMS can replicate changes, you can either manually add supplemental logging on the table level based on the primary key or unique key or utilize the endpoint setting AddSupplementalLogging = true with a DMS user having the ALTER permission on any replicated table.

Validate if there are SecureFile LOBs and the task is configured for Full LOB mode

API key: oracle-validate-securefile-lobs

This premigration assessment checks for the presence of SecureFile LOBs in tables within the task scope and verifies their LOB settings. It's important to note that SecureFile LOBs are currently supported only during FULL LOB mode. Consider assigning LOB tables to a separate task to enhance performance, as running tasks in full LOB mode may result in slower performance.

Validate whether Function-Based Indexes are being used within the tables included in the task scope.

API key: oracle-validate-function-based-indexes

This premigration assessment checks for function-based indexes on tables within the task scope. Note that AWS DMS doesn't support replicating function-based indexes. Consider creating the indexes after your migration on your target database.

Validate whether global temporary tables are being used on the tables included in the task scope.

API key: oracle-validate-global-temporary-tables

This premigration assessment checks whether global temporary tables are used within the task table-mapping scope. Note that AWS DMS doesn't support migrating or replicating global temporary tables.

Validate whether index-organized tables with an overflow segment are being used on the tables included in the task scope.

API key: oracle-validate-iot-overflow-segments

Validate whether index-organized tables with an overflow segment are being used on the tables included in the task scope. AWS DMS doesn't support CDC for index-organized tables with an overflow segment.

Validate if multilevel nesting tables are used on the tables included in the task scope.

API key: oracle-validate-more-than-one-nesting-table-level

This premigration assessment checks the nesting level of the nested table used on the task scope. AWS DMS supports only one level of table nesting.

Validate if invisible columns are used on the tables included in the task scope.

API key: oracle-validate-invisible-columns

This premigration assessment validates whether the tables used in the task scope have invisible columns. AWS DMS doesn't migrate data from invisible columns in your source database. To migrate the columns that are invisible, you need to modify them to be visible.

Validate if materialized views based on a ROWID column are used on the tables included in the task scope.

API key: oracle-validate-rowid-based-materialized-views

This premigration assessment validates whether the materialized views used in the migration are created based on the ROWID column. AWS DMS doesn't support the ROWID data type or materialized views based on a ROWID column.

Validate if Active Data Guard DML Redirect feature is used.

API key: oracle-validate-adg-redirect-dml

This premigration assessment validates whether the Active Data Guard DML Redirect feature is used. When using Oracle 19.0 as the source, AWS DMS doesn't support the Data Guard DML Redirect feature.

Validate if Hybrid Partitioned Tables are used.

API key: oracle-validate-hybrid-partitioned-tables

This premigration assessment validates whether hybrid partitioned tables are used for the tables defined in the task scope.

Validate if schema-only Oracle accounts are used

API key: oracle-validate-schema-only-accounts

This premigration assessment validates whether Schema-Only Accounts are found within the task scope.

Validate if Virtual Columns are used

API key: oracle-validate-virtual-columns

This premigration assessment validates whether the Oracle Instance has Virtual Columns in tables within the task scope.

Validate whether table names defined in the task scope contain apostrophes.

API key: oracle-validate-names-with-apostrophes

This premigration assessment validates whether the tables used in the task scope contain apostrophes. AWS DMS doesn't replicate tables with names containing apostrophes. If identified, consider renaming such tables. Alternatively, you could create a view or materialized view without apostrophes to load these tables.

Validate whether the columns defined in the task scope have XMLType, Long, or Long Raw datatypes and verify the LOB mode configuration in the task settings.

API key: oracle-validate-limited-lob-mode-for-longs

This premigration assessment validates whether the tables defined in the task scope have the datatypes XMLType, Long, or Long Raw, and checks if the task setting is configured to use Limited Size LOB Mode. AWS DMS doesn't support replicating these datatypes using FULL LOB mode. Consider changing the task setting to use Limited Size LOB mode upon identifying tables with such datatypes.

Validate whether the source Oracle version is supported by AWS DMS.

API key: oracle-validate-supported-versions-of-source

This premigration assessment validates if the source Oracle instance version is supported by AWS DMS.

Validate whether the target Oracle version is supported by AWS DMS.

API key: oracle-validate-supported-versions-of-target

This premigration assessment validates if the target Oracle instance version is supported by AWS DMS.

Validate whether the target Oracle version is supported by AWS DMS.

API key: oracle-validate-supported-versions-of-target

This premigration assessment validates if the target Oracle instance version is supported by AWS DMS.

Validate whether the DMS user has the required permissions to use data validation.

API key: oracle-prerequisites-privileges-of-validation-feature

This premigration assessment validates whether the DMS user has the necessary privileges to use DMS Data Validation. You can ignore enabling this validation if you do not intend to use data validation.

Validate if the DMS user has permissions to use Binary Reader with Oracle ASM

API key: oracle-prerequisites-privileges-of-binary-reader-asm

This premigration assessment validates whether the DMS user has the necessary privileges to use Binary Reader on the Oracle ASM instance. You can ignore enabling this assessment if your source is not an Oracle ASM instance or if you are not using Binary Reader for CDC.

Validate if the DMS user has permissions to use Binary Reader with Oracle non-ASM

API key: oracle-prerequisites-privileges-of-binary-reader-non-asm

This premigration assessment validates whether the DMS user has the necessary privileges to use Binary Reader on the Oracle non-ASM instance. This assessment is only valid if you have an Oracle non-ASM instance.

Validate if the DMS user has permissions to use Binary Reader with CopyToTempFolder method

API key: oracle-prerequisites-privileges-of-binary-reader-copy-to-temp-folder

This premigration assessment validates whether the DMS user has the necessary privileges to use the Binary Reader with the 'Copy to Temp Folder' method. This assessment is relevant only if you are planning to use CopyToTempFolder to read CDC changes while using the Binary Reader, and have an ASM instance connected to the source. You can ignore enabling this assessment if you don't intend to use the CopyToTempFolder feature.

We recommend not using the CopyToTempFolder feature because it is deprecated.

Validate if the DMS user has permissions to use Oracle Standby as a Source

API key: oracle-prerequisites-privileges-of-standby-as-source

This premigration assessment validates whether the DMS user has the necessary privileges to use a StandBy Oracle Instance as a source. You can ignore enabling this assessment if you don't intend to use a StandBy Oracle Instance as a source.

Validate if the DMS source is connected to an application container PDB

API key: oracle-check-app-pdb

This premigration assessment validates whether the DMS source is connected to an application container PDB. DMS doesn't support replication from an application container PDB.

Validate if the table has XML datatypes included in the task scope.

API key: oracle-check-xml-columns

This premigration assessment validates whether the tables used in the task scope have XML datatypes. It also checks if the task is configured for Limited LOB mode when the table contains an XML datatype. DMS only supports Limited LOB mode for migrating Oracle XML Columns.

Validate whether archivelog mode is enabled on the source database.

API key: oracle-check-archivelog-mode

This premigration assessment validates whether archivelog mode is enabled on the source database. Enabling archive log mode on the source database is necessary for DMS to replicate changes.

Validates the archivelog retention for RDS Oracle.

API key: oracle-check-archivelog-retention-rds

This premigration assessment validates whether archivelog retention on your RDS Oracle database is configured for at least 24 hours.

Validate if the table has Extended datatypes included in the task scope.

API key: oracle-check-extended-columns

This premigration assessment validates whether the tables used in the task scope have extended datatypes. Note that extended datatypes are supported only with DMS version 3.5 onwards.

Validate the length of the object name included in the task scope.

API key: oracle-check-object-30-bytes-limit

This premigration assessment validates whether the length of the object name exceeds 30 bytes. DMS doesn't support long object names (over 30 bytes).

Validate if the DMS source is connected to an Oracle PDB

API key: oracle-check-pdb-enabled

This premigration assessment validates whether the DMS source is connected to a PDB. DMS supports CDC only when using the Binary Reader with Oracle PDB as the source. The assessment also evaluates if the task is configured to use the binary reader when DMS is connected to Oracle PDB.

Validate if the table has spatial columns included in the task scope.

API key: oracle-check-spatial-columns

This premigration assessment validates whether the table has spatial columns included in the task scope. DMS supports Spatial datatypes only using Full LOB mode. The assessment also evaluates whether the task is configured to use Full LOB mode when DMS identifies spatial columns.

Validate if the DMS source is connected to an Oracle standby.

API key: oracle-check-standby-db

This premigration assessment validates whether the source is connected to an Oracle standby. DMS supports CDC only when using the binary reader with Oracle Standby as the source. The assessment also evaluates if the task is configured to use the binary reader when DMS is connected to Oracle Standby.

Validate if the source database tablespace is encrypted using TDE.

API key: oracle-check-tde-enabled

This premigration assessment validates whether the source has TDE Encryption enabled on the tablespace. DMS supports TDE only with encrypted tablespaces when using Oracle LogMiner for RDS Oracle.

Validate if the source database is Oracle ASM

API key: oracle-check-asm

This premigration assessment validates whether the source uses ASM. For improved performance with ASM configuration, consider adding parallelASMReadThreads and readAheadBlocks to the source endpoint settings.