# MariaDB assessments
This section describes individual premigration assessments for migration tasks that use a MariaDB source endpoint.
To create an individual premigration assessment using the AWS DMS API, use the listed API key for the `Include` parameter of the [ StartReplicationTaskAssessmentRun](https://docs.aws.amazon.com/dms/latest/APIReference/API_StartReplicationTaskAssessmentRun.html) action.
**Topics**
+ [Validate if the `server_id` is set to 1 or greater in the source database](#CHAP_Tasks.AssessmentReport.MariaDB.ServerID)
+ [Validate if automatic removal of binary logs is set for the source database](#CHAP_Tasks.AssessmentReport.MariaDB.AutomaticRemovalBinaryLogs)
+ [Validate that limited LOB mode only is used when BatchApplyEnabled is set to true](#CHAP_Tasks.AssessmentReport.MariaDB.LimitedLOBMode)
+ [Validate if Binary Log transaction compression is disabled](#CHAP_Tasks.AssessmentReport.MariaDB.BinaryLogTransactionCompression)
+ [Validate if DMS user has REPLICATION CLIENT and REPLICATION SLAVE privileges for the source database](#CHAP_Tasks.AssessmentReport.MariaDB.ReplicationClientSlavePrivileges)
+ [Validate if DMS user has SELECT permissions for the source database tables](#CHAP_Tasks.AssessmentReport.MariaDB.DMSUserSELECTPermissions)
+ [Validate if DMS user has necessary privileges for the MySQL-compatible database as a target](#CHAP_Tasks.AssessmentReport.MariaDB.DMSUserNecessaryPermissions)
+ [Validate if a table uses a storage engine other than Innodb](#CHAP_Tasks.AssessmentReport.MariaDB.Innodb)
+ [Validate if auto-increment is enabled on any tables used for migration](#CHAP_Tasks.AssessmentReport.MariaDB.AutoIncrement)
+ [Validate if the database binlog format is set to `ROW` to support DMS CDC](#CHAP_Tasks.AssessmentReport.MariaDB.BinlogFormat)
+ [Validate if the database binlog image is set to `FULL` to support DMS CDC](#CHAP_Tasks.AssessmentReport.MariaDB.BinlogImage)
+ [Validate if the source database is a MariaDB Read-Replica](#CHAP_Tasks.AssessmentReport.MariaDB.ReadReplica)
+ [Validate if a table has partitions, and recommend `TRUNCATE_BEFORE_LOAD` or `DO_NOTHING` for full-load task settings](#CHAP_Tasks.AssessmentReport.MariaDB.FullLoadTaskSettings)
+ [Validate if DMS supports the database version](#CHAP_Tasks.AssessmentReport.MariaDB.DatabaseVersion)
+ [Validate if the target database is configured to set `local_infile` to 1](#CHAP_Tasks.AssessmentReport.MariaDB.LocalInfile)
+ [Validate if target database has tables with foreign keys](#CHAP_Tasks.AssessmentReport.MariaDB.ForeignKeys)
+ [Validate if source tables in the task scope have cascade constraints](#CHAP_Tasks.AssessmentReport.MariaDB.Cascade)
+ [Validate if source tables in the task scope have generated columns](#CHAP_Tasks.AssessmentReport.MariaDB.GeneratedColumns)
+ [Validate if the timeout values are appropriate for a MariaDB source](#CHAP_Tasks.AssessmentReport.MariaDB.Timeout.Source)
+ [Validate if the timeout values are appropriate for a MariaDB target](#CHAP_Tasks.AssessmentReport.MariaDB.Timeout.Target)
+ [Validate `max_statement_time` database parameter](#CHAP_Tasks.AssessmentReport.MariaDB.database.parameter)
+ [Validate if Primary Key or Unique Index exist on target for Batch Apply](#CHAP_Tasks.AssessmentReport.MariaDB.batchapply)
+ [Validate if both Primary Key and Unique index exist on target for Batch Apply](#CHAP_Tasks.AssessmentReport.MariaDB.batchapply.simultaneous)
+ [Validate if secondary indexes are enabled during full load on the target database](#CHAP_Tasks.AssessmentReport.MariaDB.secondary.indexes)
+ [Validate if table has primary key or unique index when DMS validation is enabled](#CHAP_Tasks.AssessmentReport.MariaDB.dmsvalidation)
+ [Recommendation on using `MaxFullLoadSubTasks` setting](#CHAP_Tasks.AssessmentReport.MariaDB.maxfullload)
+ [Check Transformation Rule for Digits Randomize](#CHAP_Tasks.AssessmentReport.MariaDB.digits.randomize)
+ [Check Transformation Rule for Digits mask](#CHAP_Tasks.AssessmentReport.MariaDB.digits.mask)
+ [Check Transformation Rule for Hashing mask](#CHAP_Tasks.AssessmentReport.MariaDB.hash.mask)
+ [Verify that Data Validation task settings and Data Masking Digit randomization are not enabled simultaneously](#CHAP_Tasks.AssessmentReport.MariaDB.all.digits.random)
+ [Verify that Data Validation task settings and Data Masking Hashing mask are not enabled simultaneously](#CHAP_Tasks.AssessmentReport.MariaDB.all.hash.mask)
+ [Verify that Data Validation task settings and Data Masking Digit mask are not enabled simultaneously](#CHAP_Tasks.AssessmentReport.MariaDB.all.digit.mask)
+ [Check if binary log retention time is set properly](#CHAP_Tasks.AssessmentReport.MariaDB.retention.time)
+ [Check if source tables do not have invisible columns](#CHAP_Tasks.AssessmentReport.MariaDB.invisible.columns)
+ [Validate that at least one selected object exists in the source database](#CHAP_Tasks.AssessmentReport.MariaDB.selection.rules)
+ [Validate that `skipTableSuspensionForPartitionDdl` is enabled for partitioned tables](#CHAP_Tasks.AssessmentReport.MariaDB.suspension.ddl)
+ [Validate that secondary constraints and indexes (non-primary) are present in the source database](#CHAP_Tasks.AssessmentReport.MariaDB.secondary.constraints)
+ [Validate that row size of net changes table does not exceed 65535 when batch apply is enabled](#CHAP_Tasks.AssessmentReport.MariaDB.batchapply.mysql)
+ [Validate that target endpoint is not a read replica](#CHAP_Tasks.AssessmentReport.MariaDB.read.replica)
+ [Validate that number of tables to be migrated doesn't exceed 10,000](#CHAP_Tasks.AssessmentReport.MariaDB.10k.tables)
+ [Validate that binary log is enabled](#CHAP_Tasks.AssessmentReport.MariaDB.binlog.enable)
+ [Check that views from selection rules exist on source](#CHAP_Tasks.AssessmentReport.MariaDB.views)
## Validate if the `server_id` is set to 1 or greater in the source database
**API key:** `mariadb-check-server-id`
This premigration assessment validates whether the `server_id` server variable is set to 1 or greater in the source database for CDC migration type.
For more information about MariaDB endpoint limitations, see [ Using a self-managed MySQL-compatible database as a source for AWS DMS](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.MySQL.html#CHAP_Source.MySQL.CustomerManaged).
## Validate if automatic removal of binary logs is set for the source database
**API key:** `mariadb-check-expire-logs-days`
This premigration assessment validates whether your database is configured to automatically remove binary logs. The values of either `EXPIRE_LOGS_DAYS` or `BINLOG_EXPIRE_LOGS_SECONDS` global system variables should be greater than zero to prevent overuse of disk space during migration.
For more information about MariaDB endpoint limitations, see [ Using a self-managed MySQL-compatible database as a source for AWS DMS](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.MySQL.html#CHAP_Source.MySQL.CustomerManaged).
## Validate that limited LOB mode only is used when BatchApplyEnabled is set to true
**API key:** `mariadb-batch-apply-lob-mode`
When LOB columns are included in the replication, you can use `BatchApplyEnabled` in limited LOB mode only. Using other options of the LOB mode will cause the batch to fail, and AWS DMS will process the changes one by one. We recommend that you move these tables to their own tasks and use transactional apply mode instead.
For more information about the `BatchApplyEnabled` setting, see [ How can I use the DMS batch apply feature to improve CDC replication performance?](https://repost.aws/knowledge-center/dms-batch-apply-cdc-replication).
## Validate if Binary Log transaction compression is disabled
**API key:** `mariadb-check-binlog-compression`
This premigration assessment validates whether Binary Log transaction compression is disabled. AWS DMS doesn't support binary log transaction compression.
For more information, see [ Limitations on using a MySQL database as a source for AWS DMS](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.MySQL.html#CHAP_Source.MySQL.Limitations).
## Validate if DMS user has REPLICATION CLIENT and REPLICATION SLAVE privileges for the source database
**API key:** `mariadb-check-replication-privileges`
This premigration assessment validates whether the DMS user specified in the source endpoint connection settings has `REPLICATION CLIENT` and `REPLICATION SLAVE` privileges for the source database, if the DMS task migration type is CDC or full-load \$1 CDC.
For more information, see [ Using any MySQL-compatible database as a source for AWS DMS](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.MySQL.html#CHAP_Source.MySQL.Prerequisites).
## Validate if DMS user has SELECT permissions for the source database tables
**API key:** `mariadb-check-select-privileges`
This premigration assessment validates whether the DMS user specified in the source endpoint connection settings has `SELECT` permissions for the source database tables.
For more information, see [ Using any MySQL-compatible database as a source for AWS DMS](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.MySQL.html#CHAP_Source.MySQL.Prerequisites).
## Validate if DMS user has necessary privileges for the MySQL-compatible database as a target
**API key:** `mariadb-check-target-privileges`
This premigration assessment validates whether the DMS user specified in the target endpoint connection settings has necessary privileges for the MySQL-compatible database as a target.
For more information, see [ Using any MySQL-compatible database as a source for AWS DMS](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.MySQL.html#CHAP_Source.MySQL.Prerequisites).
## Validate if a table uses a storage engine other than Innodb
**API key:** `mariadb-check-table-storage-engine`
This premigration assessment validates whether the storage engine used for any table in the Source MariaDB database is an engine other than Innodb. DMS creates target tables with the InnoDB storage engine by default. If you need to use a storage engine other than InnoDB, you must manually create the table on the target database and configure your DMS task to use `TRUNCATE_BEFORE_LOAD` or `DO_NOTHING` as the full-load task setting. For more information about full-load task settings, see [Full-load task settings](CHAP_Tasks.CustomizingTasks.TaskSettings.FullLoad.md).
For more information about MariaDB endpoint limitations, see [Limitations on using a MySQL database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.Limitations).
## Validate if auto-increment is enabled on any tables used for migration
**API key:** `mariadb-check-auto-increment`
This premigration assessment validates whether the source tables that are used in the task have auto-increment enabled. DMS doesn't migrate the AUTO\$1INCREMENT attribute on a column to a target database.
For more information about MariaDB endpoint limitations, see [Limitations on using a MySQL database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.Limitations). For information about handling identity columns in MariaDB, see [ Handle IDENTITY columns in AWS DMS: Part 2](https://aws.amazon.com/blogs/database/handle-identity-columns-in-aws-dms-part-2/).
## Validate if the database binlog format is set to `ROW` to support DMS CDC
**API key:** `mariadb-check-binlog-format`
This premigration assessment validates whether the source database binlog format is set to `ROW` to support DMS Change Data Capture (CDC).
To set the binlog format to `ROW`, do the following:
+ For Amazon RDS, use the database's parameter group. For information about using an RDS parameter group, see [ Configuring MySQL binary logging](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_LogAccess.MySQL.BinaryFormat.html) in the *Amazon RDS User Guide*.
+ For databases hosed on-premises or on Amazon EC2, set the `binlog_format` value in `my.ini` (Microsoft Windows) or `my.cnf` (UNIX).
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 self-hosted MariaDB servers, see [Using a self-managed MySQL-compatible database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.CustomerManaged).
## Validate if the database binlog image is set to `FULL` to support DMS CDC
**API key:** `mariadb-check-binlog-image`
This premigration assessment checks whether the source database's binlog image is set to `FULL`. In MariaDB, the `binlog_row_image` variable determines how a binary log event is written when using the `ROW` format. To ensure compatibility with DMS and support CDC, set the `binlog_row_image` variable to `FULL`. This setting ensures that DMS receives sufficient information to construct the full Data Manipulation Language (DML) for the target database during migration.
To set the binlog image to `FULL`, do the following:
+ For Amazon RDS, this value is `FULL` by default.
+ For databases hosed on-premises or on Amazon EC2, set the `binlog_row_image` value in `my.ini` (Microsoft Windows) or `my.cnf` (UNIX).
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 self-hosted MariaDB servers, see [Using a self-managed MySQL-compatible database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.CustomerManaged).
## Validate if the source database is a MariaDB Read-Replica
**API key:** `mariadb-check-database-role`
This premigration assessment verifies whether the source database is a read replica. To enable CDC support for DMS when connected to a read replica, set the `log_slave_updates` parameter to `True`. For more information about using a self-managed MySQL database, see [Using a self-managed MySQL-compatible database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.CustomerManaged).
To set the `log_slave_updates` value to `True`, do the following:
+ For Amazon RDS, use the database's parameter group. For information about using RDS database parameter groups, see [ Working with parameter groups ](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_WorkingWithParamGroups.html) in the *Amazon RDS User Guide*.
+ For databases hosed on-premises or on Amazon EC2, set the `log_slave_updates` value in `my.ini` (Microsoft Windows) or `my.cnf` (UNIX).
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 a table has partitions, and recommend `TRUNCATE_BEFORE_LOAD` or `DO_NOTHING` for full-load task settings
**API key:** `mariadb-check-table-partition`
This premigration assessment checks for the presence of tables with partitions in the source database. DMS creates tables without partitions on the MariaDB target. To migrate partitioned tables to a partitioned table on the target, you must do the following:
+ Pre-create the partitioned tables in the target MariaDB database.
+ Configure your DMS task to use `TRUNCATE_BEFORE_LOAD` or `DO_NOTHING` as the full-load task setting.
For more information about MariaDB endpoint limitations, see [Limitations on using a MySQL database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.Limitations).
## Validate if DMS supports the database version
**API key:** `mariadb-check-supported-version`
This premigration assessment verifies whether the source database version is compatible with DMS. CDC is not supported with Amazon RDS MariaDB versions 10.4 or lower, or MySQL versions greater than 10.11. For more information about supported MariaDB versions, see [Source endpoints for data migration](CHAP_Introduction.Sources.md#CHAP_Introduction.Sources.DataMigration).
## Validate if the target database is configured to set `local_infile` to 1
**API key:** `mariadb-check-target-localinfile-set`
This premigration assessment checks whether the `local_infile` parameter in the target database is set to 1. DMS requires the 'local\$1infile' parameter to be set to 1 during full load in your target database. For more information, see [Migrating from MySQL to MySQL using AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.Homogeneous).
This assessment is only valid for a full-load task.
## Validate if target database has tables with foreign keys
**API key:** `mariadb-check-fk-target`
This premigration assessment checks whether a full load or full and CDC task migrating to a MariaDB database has tables with foreign keys. The default setting in DMS is to load tables in alphabetical order. Tables with foreign keys and referential integrity constraints can cause the load to fail, as the parent and child tables may not be loaded at the same time.
For more information about referential integrity in DMS, see **Working with indexes, triggers, and referential integrity constraints** in the [Improving the performance of an AWS DMS migration](CHAP_BestPractices.md#CHAP_BestPractices.Performance) topic.
## Validate if source tables in the task scope have cascade constraints
**API key:** `mariadb-check-cascade-constraints`
This premigration assessment checks if any of the MariaDB source tables have cascade constraints. Cascade constraints are not migrated or replicated by DMS tasks, because MariaDB doesn't record the changes for these events in the binlog. While AWS DMS doesn't support these constraints, you can use workarounds for relational database targets.
For information about supporting cascase constrains and other constraints, see [Indexes, Foreign Keys, or Cascade Updates or Deletes Not Migrated](CHAP_Troubleshooting.md#CHAP_Troubleshooting.MySQL.FKsAndIndexes) in the **Troubleshooting migration tasks in AWS DMS** topic.
## Validate if source tables in the task scope have generated columns
**API key:** `mariadb-check-generated-columns`
This premigration assessment checks whether any of the MariaDB source tables have generated columns. DMS tasks don't migrate or replicate generated columns.
For information about how to migrate generated columns, see [Connections to a target MySQL instance are disconnected during a task](CHAP_Troubleshooting.md#CHAP_Troubleshooting.MySQL.ConnectionDisconnect).
## Validate if the timeout values are appropriate for a MariaDB source
**API key:** `mariadb-check-source-network-parameter`
This premigration assessment checks whether a task’s MariaDB source endpoint has the `net_read_timeout`, `net_write_timeout` and `wait_timeout` settings set to at least 300 seconds. This is needed to prevent disconnects during the migration.
For more information, see [Connections to a target MySQL instance are disconnected during a task](CHAP_Troubleshooting.md#CHAP_Troubleshooting.MySQL.ConnectionDisconnect).
## Validate if the timeout values are appropriate for a MariaDB target
**API key:** `mariadb-check-target-network-parameter`
This premigration assessment checks whether a task’s MariaDB target endpoint has the `net_read_timeout`, `net_write_timeout` and `wait_timeout` settings set to at least 300 seconds. This is needed to prevent disconnects during the migration.
For more information, see [Connections to a target MySQL instance are disconnected during a task](CHAP_Troubleshooting.md#CHAP_Troubleshooting.MySQL.ConnectionDisconnect).
## Validate `max_statement_time` database parameter
**API key:**`mariadb-check-max-statement-time`
AWS DMS validates that the database source parameter `max_statement_time` is set to a value other than 0. It is required to set this parameter to 0 to accommodate the DMS full load process. You can consider changing the parameter value after the full load is completed, as setting it to a value other than 0 may result is loss of data.
## Validate if Primary Key or Unique Index exist on target for Batch Apply
**API key:** `mariadb-check-batch-apply-target-pk-ui-absence`
Batch apply is only supported on tables with Primary Keys or Unique Indexes on the target table. Tables without Primary Keys or Unique Indexes will cause the batch to fail, and changes will be processed one by one. It is advisable to move such tables to their own tasks and utilize transactional apply mode instead. Alternatively, you can create a unique key on the target table.
For more information, see [Using a MySQL-compatible database as a target for AWS Database Migration Service](CHAP_Target.MySQL.md).
## Validate if both Primary Key and Unique index exist on target for Batch Apply
**API key:** `mariadb-check-batch-apply-target-pk-ui-simultaneously`
Batch apply is only supported on tables with Primary Keys or Unique Indexes on the target table. Tables with Primary Keys and Unique Indexes simultaneously cause the batch to fail, and changes are processed one by one. It is advisable to move such tables to their own tasks and utilize transactional apply mode instead. Alternatively, you can drop a unique key(s) or primary key on the target table and rebuild it if you are doing migration.
For more information, see [Using a MySQL-compatible database as a target for AWS Database Migration Service](CHAP_Target.MySQL.md).
## Validate if secondary indexes are enabled during full load on the target database
**API key:** `mariadb-check-secondary-indexes`
You must consider disabling or removing the secondary indexes from the target database. Secondary indexes can affect your migration performance during full load. It is advisable to enable secondary indexes before applying the cached changes.
For more information, see [Best practices for AWS Database Migration Service](CHAP_BestPractices.md).
## Validate if table has primary key or unique index when DMS validation is enabled
**API key:** `mariadb-check-pk-validity`
Data validation requires that the table has a primary key or unique index on both source and target.
For more information, see [AWS DMS data validation](CHAP_Validating.md).
## Recommendation on using `MaxFullLoadSubTasks` setting
This assessment checks the number of tables included in the task and recommends increasing the `MaxFullLoadSubTasks` parameter for optimal performance during the full load process. By default, AWS DMS migrates 8 tables simultaneously. Changing the `MaxFullLoadSubTasks` parameter to a higher value will improve the full load performance.
For more information, see [Full-load task settings](CHAP_Tasks.CustomizingTasks.TaskSettings.FullLoad.md).
## Check Transformation Rule for Digits Randomize
**API key**: `mariadb-datamasking-digits-randomize`
This assessment validates whether columns used in table mappings are compatible with the Digits Randomize transformation rule. Additionally, the assessment checks if any columns selected for transformation are part of primary keys, unique constraints, or foreign keys, as applying digits randomize transformations does not guarantee any uniqueness.
## Check Transformation Rule for Digits mask
**API key**: `mariadb-datamasking-digits-mask`
This assessment validates whether any columns used in the table mapping are not supported by the Digits Mask transformation rule. Additionally, the assessment checks if any columns selected for transformation are part of primary keys, unique constraints, or foreign keys, as applying Digits Mask transformations to such columns could cause DMS task failures since uniqueness cannot be guaranteed.
## Check Transformation Rule for Hashing mask
**API key**: `mariadb-datamasking-hash-mask`
This assessment validates whether any of the columns used in the table mapping are not supported by the Hashing Mask transformation rule. It also checks if the length of the source column exceeds 64 characters. Ideally, the target column length should be greater than 64 characters to support hash masking. Additionally, the assessment checks if any columns selected for transformation are part of primary keys, unique constraints, or foreign keys, as applying digits randomize transformations does not guarantee any uniqueness.
## Verify that Data Validation task settings and Data Masking Digit randomization are not enabled simultaneously
**API key**: `all-to-all-validation-with-datamasking-digits-randomize`
This premigration assessment verifies that Data Validation setting and Data Masking Digit randomization are not simultaneously enabled, as these features are incompatible.
## Verify that Data Validation task settings and Data Masking Hashing mask are not enabled simultaneously
**API key**: `all-to-all-validation-with-datamasking-hash-mask`
This premigration assessment verifies that Data Validation setting and Data Masking Hashing mask are not simultaneously enabled, as these features are incompatible.
## Verify that Data Validation task settings and Data Masking Digit mask are not enabled simultaneously
**API key**: `all-to-all-validation-with-digit-mask`
This premigration assessment verifies that Data Validation setting and Data Masking Digit mask are not simultaneously enabled, as these features are incompatible.
## Check if binary log retention time is set properly
**API key**: `mariadb-check-binlog-retention-time`
This premigration assessment validates whether the value of '`binlog retention hours`' is larger than 24 hours.
## Check if source tables do not have invisible columns
**API key**: `mariadb-check-invisible-columns`
This premigration assessment validates whether source tables do not have invisible columns. AWS DMS does not migrate data from invisible columns in your source database.
## Validate that at least one selected object exists in the source database
**API key**: `all-check-source-selection-rules`
This premigration assessment verifies that at least one object specified in the selection rules exists in the source database, including pattern matching for wildcard-based rules.
## Validate that `skipTableSuspensionForPartitionDdl` is enabled for partitioned tables
**API key**: `mariadb-check-skip-table-suspension-partition-ddl`
This premigration assessment detects partitioned tables in the source database and verifies the `skipTableSuspensionForPartitionDdl` parameter setting. Failure to set this parameter may result in unnecessary table suspensions during migration.
For more information, see [Limitations on using a MySQL database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.Limitations).
## Validate that secondary constraints and indexes (non-primary) are present in the source database
**API key**: `all-check-secondary-constraints`
This premigration assessment verifies that secondary constraints and indexes (foreign keys, check constraints, non-clustered indexes) are present in the source database.
## Validate that row size of net changes table does not exceed 65535 when batch apply is enabled
**API key**: `all-check-for-batch-apply-to-mysql`
The premigration assessment checks if any table contains rows exceeding 65,535 bytes in size. When batch apply is enabled, AWS DMS cannot create temporary tables for rows exceeding this size due to engine limitations.
## Validate that target endpoint is not a read replica
**API key**: `all-check-target-read-replica`
This premigration assessment verifies that the target endpoint is not configured as a read replica. AWS DMS requires write access to the target database and cannot replicate to read-only replicas.
## Validate that number of tables to be migrated doesn't exceed 10,000
**API key**: `mariadb-check-10k-tables`
This premigration assessment validates whether the number of tables to migrate exceeds 10,000 based on your table selection.
## Validate that binary log is enabled
**API key**: `mariadb-check-binlog-enabled`
This premigration assessment validates whether binary logging is enabled on the source database.
For more information, see [Using a self-managed MySQL-compatible database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.CustomerManaged).
## Check that views from selection rules exist on source
**API key**: `mariadb-check-views`
This premigration assessment validates whether views are used, as AWS DMS does not support views migration for MariaDB.
For more information, see [Limitations on using a MySQL database as a source for AWS DMS](CHAP_Source.MySQL.md#CHAP_Source.MySQL.Limitations).