Migrate data from a self-managed PostgreSQL database to an AnalyticDB for PostgreSQL instance - Data Transmission Service

This topic describes how to use Data Transmission Service (DTS) to migrate data from a self-managed PostgreSQL database to an AnalyticDB for PostgreSQL instance.

Prerequisites

You have created the destination AnalyticDB for PostgreSQL instance. For more information, see Create an instance.
Note
For information about the supported versions of the source and destination databases, see Overview of data migration scenarios.
The available disk space of the destination AnalyticDB for PostgreSQL instance is larger than the disk space occupied by the source self-managed PostgreSQL database.

Precautions

Note

During schema migration, DTS migrates foreign keys from the source database to the destination database.
During full data migration and incremental data migration, DTS temporarily disables the constraint check and cascade operations on foreign keys at the session level. If you perform the cascade update and delete operations on the source database during data migration, data inconsistency may occur.

Category	Description
Source database limits	The server to which the source database belongs must have sufficient outbound bandwidth. Otherwise, the data migration speed decreases. The tables to be migrated must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records. The name of the source database cannot contain hyphens (-). Example: dts-testdata. If you select tables as the objects to be migrated and you need to edit the tables, such as renaming tables or columns, in the destination database, you can migrate up to 1,000 tables in a single data migration task. If you run a task to migrate more than 1,000 tables, a request error occurs. In this case, we recommend that you configure multiple tasks to migrate the tables, or configure a task to migrate the entire database. If you need to migrate incremental data, you must make sure that the following requirements are met: The value of the wal_level parameter must be set to logical. For incremental data migration, the write-ahead logging (WAL) logs of the source database must be stored for more than 24 hours. For full data and incremental data migration, the WAL logs of the source database must be stored for at least seven days. Otherwise, DTS may fail to obtain the WAL logs and the task may fail. In exceptional circumstances, data inconsistency or loss may occur. After full data migration is complete, you can set the retention period to more than 24 hours. Make sure that you set the retention period of WAL logs based on the preceding requirements. Otherwise, the service reliability and performance stated in the Service Level Agreement (SLA) of DTS may not be guaranteed. Limits on operations to be performed on the source database: If you perform a primary/secondary switchover on a self-managed PostgreSQL database, the data migration task fails. During full data migration, do not perform DDL operations to change the schemas of databases or tables. Otherwise, the data migration task fails. If you perform only full data migration, do not write data to the source database during data migration. Otherwise, data inconsistency may occur between the source and destination databases. To ensure data consistency, we recommend that you select full data migration and incremental data migration as the migration types. If one or more long-running transactions exist in the source database and incremental data is migrated in the data migration task, the WAL logs generated before the long-running transactions in the source database are committed may be accumulated. As a result, the disk space of the source database may be insufficient.
Other limits	The destination table cannot be an append-optimized (AO) table. The migration of DATATYPE, SEQUENCE, INDEX, PROCEDURE, FUNCTION, VIEW, OPERATOR, DEFAULT_CONSTRAINT, UK, PK, RULE, DOMAIN, AGGREGATE, EXTENSION, FK, and TRIGGER objects is not supported. If you use column mapping for partial table migration or if the source and destination table schemas are inconsistent, data in the columns that exist in the source database but not in the destination database is lost. If the migration instance includes an incremental data migration task, you must run the `ALTER TABLE schema.table REPLICA IDENTITY FULL;` command on the table to be migrated in the source database before you write data to it in the following two scenarios. This ensures data consistency for the table migration. During the execution of this command, we recommend that you do not perform table locking operations. Otherwise, the table will be locked. If you skip the relevant check in the precheck, DTS automatically runs this command when the instance is initialized. When the instance runs for the first time. When the migration object granularity is Schema, and a new table is created in the schema to be migrated or a table to be migrated is rebuilt using the RENAME command. Note In the command, replace `schema` and `table` with the schema name and table name of the data to be migrated. We recommend that you perform this operation during off-peak hours. DTS creates the following temporary tables in the source database to obtain the DDL statements of incremental data, the schemas of incremental tables, and the heartbeat information. During data migration, do not delete temporary tables in the source database. Otherwise, the data migration task may fail. After the DTS instance is released, temporary tables are automatically deleted. `public.dts_pg_class`, `public.dts_pg_attribute`, `public.dts_pg_type`, `public.dts_pg_enum`, `public.dts_postgres_heartbeat`, `public.dts_ddl_command`, `public.dts_args_session`, and `public.aliyun_dts_instance`. To ensure that the latency of incremental data migration is accurate, DTS creates a heartbeat table named `dts_postgres_heartbeat` in the source database. During incremental data migration, DTS creates a replication slot for the source database. The replication slot is prefixed with `dts_sync_`. DTS automatically clears historical data in the replication slot every 90 minutes to reduce storage usage. Note If the data migration task is released or fails, DTS automatically clears the replication slot. If a primary/secondary switchover is performed on the ApsaraDB RDS for PostgreSQL instance, you must log on to the secondary database to manually clear the replication slot. A data migration task can migrate data from only one database. To migrate data from multiple databases, you must create a data migration task for each database. DTS does not support migrating TimescaleDB extension tables or tables with cross-schema inheritance relationships. If a table to be migrated contain a primary key, the primary key column in the destination table must be the same as that of the source table. If a table to be migrated does not contain a primary key, the primary key column and the distribution key in the destination table must be the same. A unique key (primary key column contained) in the destination table must contain all columns of its distribution key. Before you migrate data, evaluate the impact of data migration on the performance of the source instance and destination cluster. We recommend that you migrate data during off-peak hours. During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads of the database servers. During full data migration, concurrent INSERT operations cause fragmentation in the tables of the destination database. After full data migration is complete, the tablespace of the destination database is larger than that of the source database. Make sure that the precision settings for columns of the FLOAT or DOUBLE data type meet your business requirements. DTS uses the `ROUND(COLUMN,PRECISION)` function to retrieve values from columns of the FLOAT or DOUBLE data type. If you do not specify a precision, DTS sets the precision for the FLOAT data type to 38 digits and the precision for the DOUBLE data type to 308 digits. DTS attempts to resume data migration tasks that failed within the last seven days. Before you switch workloads to the destination database, you must stop or release the failed tasks. You can also execute the `REVOKE` statement to revoke the write permissions from the accounts that are used by DTS to access the destination database. Otherwise, the data in the source database overwrites the data in the destination database after the failed task is resumed. DTS does not check the validity of metadata such as sequences. You must manually check the validity of metadata. After you switch your business to the destination instance, the newly written sequences do not increment from the maximum value of the sequences in the source database. Before the switchover, you must query the maximum value of the corresponding sequence in the source database and then set it as the initial value of the corresponding sequence in the destination database. The following command queries the sequence values in the source database: `do language plpgsql $$ declare nsp name; rel name; val int8; begin for nsp,rel in select nspname,relname from pg_class t2 , pg_namespace t3 where t2.relnamespace=t3.oid and t2.relkind='S' loop execute format($_$select last_value from %I.%I$_$, nsp, rel) into val; raise notice '%', format($_$select setval('%I.%I'::regclass, %s);$_$, nsp, rel, val+1); end loop; end; $$;` Note The SQL statements output by the preceding command contain all sequences in the source database. Run the statements in the destination database as needed. If an instance fails, DTS helpdesk will try to recover the instance within 8 hours. During the recovery process, operations such as restarting the instance and adjusting parameters may be performed. Note When parameters are adjusted, only the parameters of the DTS instance are modified. The parameters of the database are not modified. The parameters that may be modified include but are not limited to those described in Modify instance parameters. When you migrate a partitioned table, you must include both the parent table and its child tables as synchronization objects. Otherwise, data inconsistency may occur for the partitioned table. Note The parent table of a PostgreSQL partitioned table does not directly store data. All data is stored in the child tables. The synchronization task must include the parent table and all its child tables. Otherwise, data in the child tables may not be synchronized, leading to data inconsistency between the source and destination.

Billing

Migration type	Instance configuration fee	Internet traffic fee
Schema migration and full data migration	Free of charge.	When the Access Method parameter of the destination database is set to Public IP Address, you are charged for Internet traffic. For more information, see Billing overview.
Incremental data migration	Charged. For more information, see Billing overview.

Migration types

Schema migration
DTS migrates the schemas of the selected objects from the source database to the destination database.
Full data migration
DTS migrates the historical data of required objects from the source database to the destination database.
Incremental data migration
After full data migration is complete, DTS migrates incremental data from the source database to the destination database. Incremental data migration allows data to be migrated smoothly without interrupting the services of self-managed applications during data migration.

SQL operations that support incremental migration

Operation type	SQL statement
DML	INSERT, UPDATE, and DELETE Note When data is written to the destination AnalyticDB for PostgreSQL instance, the UPDATE statement is automatically converted to the REPLACE INTO statement. If the UPDATE statement is executed on primary keys, the UPDATE statement is converted to the DELETE and INSERT statements.
DDL	DDL operations can be migrated only in the data migration tasks that are created after October 1, 2020. Important To use a data migration task created before May 12, 2023 to migrate DDL operations, you must create a trigger and a function in the source database to capture DDL information before you configure the data migration task. For more information, see Use triggers and functions to implement incremental DDL migration for PostgreSQL databases. Incremental data migration does not support data of the BIT type. The database account of the source database must be a privileged account. DTS supports the following DDL statements in data migration tasks: CREATE TABLE and DROP TABLE ALTER TABLE, including RENAME TABLE, ADD COLUMN, ADD COLUMN DEFAULT, ALTER COLUMN TYPE, DROP COLUMN, ADD CONSTRAINT, ADD CONSTRAINT CHECK, and ALTER COLUMN DROP DEFAULT TRUNCATE TABLE (The database engine version of the source PolarDB for PostgreSQL cluster must be PostgreSQL V11 or later.) CREATE INDEX ON TABLE Important You cannot migrate additional information of DDL statements, such as CASCADE or RESTRICT. You cannot migrate the DDL statements from a session in which the `SET session_replication_role = replica` statement is executed. You cannot migrate DDL statements that are executed by invoking functions. If the SQL statements submitted by the source database at a time contain both DML and DDL statements, DTS does not migrate the DDL statements. If the SQL statements submitted by the source database at a time contain DDL statements that are not to be migrated, DTS does not migrate the DDL statements. The CREATE SEQUENCE statement is not supported.

Permissions required for database accounts

Database	Schema migration	Full migration	Incremental migration
Self-managed PostgreSQL	USAGE permission on pg_catalog.	Permissions for SELECT statement on the migration objects.	Superuser permissions.
AnalyticDB for PostgreSQL	Permissions of the schema owner. Note You can also use the initial account.

To create a database account and grant permissions:

For a self-managed PostgreSQL database, see the official documentation for the CREATE USER and GRANT syntax.
For an AnalyticDB for PostgreSQL instance, see Create and manage a user and User permission management.

Preparations

Note

For more information about how to make preparations if your source database is an Amazon RDS for PostgreSQL instance, see the Before you begin section of the "Migrate incremental data from an Amazon RDS for PostgreSQL instance to an ApsaraDB RDS for PostgreSQL instance" topic. For more information about how to make preparations if your source database is an Amazon Aurora PostgreSQL instance, see the Preparation 1: Edit the inbound rule of the Amazon Aurora PostgreSQL instance section of the "Migrate full data from an Amazon Aurora PostgreSQL instance to an ApsaraDB RDS for PostgreSQL instance" topic.
In this example, a self-managed PostgreSQL database that runs on a Linux server is used.

If the version of the self-managed PostgreSQL database is 10.1 or later, you must perform the following operations before you configure a data migration task.

Log on to the server on which the self-managed PostgreSQL database resides.

Modify the postgresql.conf configuration file. Set the wal_level parameter to logical, and make sure that the values of the max_wal_senders and max_replication_slots parameters are greater than the sum of the number of used replication slots in the self-managed PostgreSQL database and the number of DTS instances whose source database is the self-managed PostgreSQL database.

# - Settings -

wal_level = logical			# minimal, replica, or logical
					# (change requires restart)

......

# - Sending Server(s) -

# Set these on the master and on any standby that will send replication data.

max_wal_senders = 10		# max number of walsender processes
				# (change requires restart)
#wal_keep_segments = 0		# in logfile segments, 16MB each; 0 disables
#wal_sender_timeout = 60s	# in milliseconds; 0 disables

max_replication_slots = 10	# max number of replication slots
				# (change requires restart)

Note

After you modify the configuration file, restart the self-managed PostgreSQL database to make the parameter settings take effect.

Add the CIDR blocks of DTS servers to the pg_hba.conf configuration file of the self-managed PostgreSQL database. Add only the CIDR blocks of the DTS servers that reside in the same region as the destination database. For more information, see Add DTS server IP addresses to a whitelist.
Note
- After you modify the configuration file, execute the SELECT pg_reload_conf(); statement or restart the self-managed PostgreSQL database to make the parameter settings take effect.
- For more information about the pg_hba.conf configuration file, see The pg_hba.conf File. Skip this step if you have set the IP address in the pg_hba.conf file to 0.0.0.0/0. The following figure shows the configurations.
Create the corresponding database and schema in the destination cluster based on the information of the database and schema of the object to be migrated.

If the version of the self-managed PostgreSQL database is 9.4.8 to 10.0, you must perform the following operations before you configure a data migration task:

Download the PostgreSQL source code from the official website, compile the source code, and install PostgreSQL.
1. Download the source code from the PostgreSQL official website based on the version of the self-managed PostgreSQL database.
2. Run the sudo ./configure, sudo make, and sudo make install commands in sequence to configure and compile the source code, and install PostgreSQL.
  Important
  When you compile and install PostgreSQL, the OS version of PostgreSQL must be consistent with the version of the GNU compiler collection (GCC).
  If an error occurs when you run the sudo ./configure command, you can modify the command based on the error message. For example, if the error message is readline library not found. Use --without-readline to disable readline support., you can modify the command to sudo ./configure --without-readline.
  If you use another method to install PostgreSQL, you must compile the ali_decoding plug-in in a test environment that has the same operating system version and GCC version.

Download the ali_decoding plug-in provided by DTS, and compile and install the plug-in.

Download ali_decoding.
Copy the ali_decoding directory to the contrib directory of PostgreSQL that is compiled and installed.

Go to the ali_decoding directory and replace the content of the Makefile file with the following script:

# contrib/ali_decoding/Makefile
MODULE_big = ali_decoding
MODULES = ali_decoding
OBJS    = ali_decoding.o

DATA = ali_decoding--0.0.1.sql ali_decoding--unpackaged--0.0.1.sql

EXTENSION = ali_decoding

NAME = ali_decoding

#subdir = contrib/ali_decoding
#top_builddir = ../..
#include $(top_builddir)/src/Makefile.global
#include $(top_srcdir)/contrib/contrib-global.mk

#PG_CONFIG = /usr/pgsql-9.6/bin/pg_config
#pgsql_lib_dir := $(shell $(PG_CONFIG) --libdir)
#PGXS := $(shell $(PG_CONFIG) --pgxs)
#include $(PGXS)

# Run the following commands to install the ali_decoding plug-in:
ifdef USE_PGXS
PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
include $(PGXS)
else
subdir = contrib/ali_decoding
top_builddir = ../..
include $(top_builddir)/src/Makefile.global
include $(top_srcdir)/contrib/contrib-global.mk
endif

Go to the ali_decoding directory, and run the sudo make and sudo make install commands in sequence to compile the ali_decoding plug-in and obtain the files that are required to install the ali_decoding plug-in.
Copy the files to the specified directories.

Create the corresponding database and schema in the destination cluster based on the information of the database and schema of the object to be migrated.

Procedure

Use one of the following methods to go to the Data Migration page and select the region in which the data migration instance resides.
DTS console
1. Log on to the DTS console.
2. In the left-side navigation pane, click Data Migration.
3. In the upper-left corner of the page, select the region in which the data migration instance resides.
DMS console
Note
The actual operation may vary based on the mode and layout of the DMS console. For more information, see Simple mode and Customize the layout and style of the DMS console.
1. Log on to the DMS console.
2. In the top navigation bar, move the pointer over Data + AI > DTS (DTS) > Data Migration.
3. From the drop-down list to the right of Data Migration Tasks, select the region in which the data synchronization instance resides.
Click Create Task to go to the task configuration page.

Configure the source and destination databases. The following table describes the parameters.

Warning

After you select the source and destination instances, we recommend that you carefully read the Limits section at the top of the page. This helps ensure that you can successfully create and execute the migration task.

Category	Configuration	Description
N/A	Task Name	The name of the DTS task. DTS automatically generates a task name. We recommend that you specify an informative name that makes it easy to identify the task. You do not need to specify a unique task name.
Source Database	Select Existing Connection	If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections. Note In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list. If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.
	Database Type	Select PostgreSQL.
	Access Method	Select the deployment location of the source database. This topic uses a Self-managed Database on ECS as an example to describe the configuration process. Note If you select another method to access the self-managed database, you must perform corresponding preparations. For more information, see Preparations.
	Instance Region	Select the region where the self-managed PostgreSQL database resides.
	ECS Instance ID	Enter the ID of the ECS instance on which the self-managed PostgreSQL database is deployed.
	Port Number	The service port of the self-managed PostgreSQL database. Default value: 5432.
	Database Name	Enter the name of the database in the self-managed PostgreSQL database to which the migration objects belong.
	Database Account	Enter the database account of the self-managed PostgreSQL database. For information about the required permissions, see Permissions required for database accounts.
	Database Password	The password that is used to access the database instance.
	Encryption	Specifies whether to encrypt the connection to the source database. You can configure this parameter based on your business requirements. In this example, Non-encrypted is selected. If you want to establish an SSL-encrypted connection to the source database, perform the following steps: Select SSL-encrypted, upload CA Certificate, Client Certificate, and Private Key of Client Certificate as needed, and then specify Private Key Password of Client Certificate. Note If you set Encryption to SSL-encrypted for a self-managed PostgreSQL database, you must upload CA Certificate. If you want to use the client certificate, you must upload Client Certificate and Private Key of Client Certificate and specify Private Key Password of Client Certificate. For information about how to configure SSL encryption for an ApsaraDB RDS for PostgreSQL instance, see SSL encryption.
Destination Database	Select Existing Connection	If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections. Note In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list. If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.
	Database Type	Select AnalyticDB for PostgreSQL.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the destination AnalyticDB for PostgreSQL instance resides.
	Instance ID	Select the ID of the destination AnalyticDB for PostgreSQL instance.
	Database Name	Enter the name of the database in the destination AnalyticDB for PostgreSQL instance to which the migration objects belong.
	Database Account	Enter the database account of the destination AnalyticDB for PostgreSQL instance. For information about the required permissions, see Permissions required for database accounts.
	Database Password	The password that is used to access the database instance.

Click Test Connectivity and Proceed in the lower part of the page.
Note
- Make sure that the CIDR blocks of DTS servers can be automatically or manually added to the security settings of the source and destination databases to allow access from DTS servers. For more information, see Add DTS server IP addresses to a whitelist.
- If the source or destination database is a self-managed database and its Access Method is not set to Alibaba Cloud Instance, click Test Connectivity in the CIDR Blocks of DTS Servers dialog box.

Configure the objects to be migrated.

Configuration	Description
Migration Types	To perform only full data migration, select Schema Migration and Full Data Migration. To ensure service continuity during data migration, select Schema Migration, Full Data Migration, and Incremental Data Migration. Note If you do not select Schema Migration, make sure a database and a table are created in the destination database to receive data and the object name mapping feature is enabled in Selected Objects. If you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
Processing Mode of Conflicting Tables	Precheck and Report Errors: checks whether the destination database contains tables that use the same names as tables in the source database. If the source and destination databases do not contain tables that have identical table names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started. Note If the source and destination databases contain tables with identical names and the tables in the destination database cannot be deleted or renamed, you can use the object name mapping feature to rename the tables that are migrated to the destination database. For more information, see Map object names. Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases. Warning If you select Ignore Errors and Proceed, data inconsistency may occur and your business may be exposed to the following potential risks: If the source and destination databases have the same schema, and a data record has the same primary key as an existing data record in the destination database, the following scenarios may occur: During full data migration, DTS does not migrate the data record to the destination database. The existing data record in the destination database is retained. During incremental data migration, DTS migrates the data record to the destination database. The existing data record in the destination database is overwritten. If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
DDL and DML Operations to Be Synchronized	Select the SQL operations for incremental migration at the instance level. For information about the supported operations, see SQL operations that support incremental migration. Note To select SQL operations for incremental migration at the database or table level, right-click a migration object in the Selected Objects section and select the required SQL operations in the pop-up dialog box.
Storage Engine Type	The storage engine type of the destination table. Default value: Beam. Specify this parameter based on your business requirements. Note This parameter is available only the minor version of the destination AnalyticDB for PostgreSQL instance is v7.0.6.6 or later and you specify Schema Migration for the Migration Types parameter.
Capitalization of Object Names in Destination Instance	The capitalization of database names, table names, and column names in the destination instance. By default, DTS default policy is selected. You can select other options to make sure that the capitalization of object names is consistent with that of the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.
Source Objects	Select one or more objects from the Source Objects section. Click the icon to add the objects to the Selected Objects section. Note You can select columns, tables, or schemas as the objects to be migrated. If you select tables or columns as the objects to be migrated, DTS does not migrate other objects, such as views, triggers, or stored procedures, to the destination database.
Selected Objects	To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object. To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time. Note If you use the object name mapping feature, other objects that depend on the renamed object may fail to be migrated. To set a WHERE condition to filter data, right-click the table to be migrated in the Selected Objects box and set the filter condition in the dialog box that appears. For more information, see Set filter conditions. To select SQL operations for migration at the database or table level, right-click the object to be migrated in the Selected Objects box, and in the dialog box that appears, select the desired SQL operations.

Click Next: Advanced Settings to configure advanced settings.

Configuration	Description
Dedicated Cluster for Task Scheduling	By default, DTS schedules the data migration task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data migration tasks, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.
Retry Time for Failed Connections	The retry time range for failed connections. If the source or destination database fails to be connected after the data migration task is started, DTS immediately retries a connection within the retry time range. Valid values: 10 to 1,440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS is reconnected to the source and destination databases within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you specify different retry time ranges for multiple data migration tasks that share the same source or destination database, the value that is specified later takes precedence. When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business requirements. You can also release the DTS instance at the earliest opportunity after the source database and destination instance are released.
Retry Time for Other Issues	The retry time range for other issues. For example, if DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set the parameter to a value greater than 10. If the failed operations are successfully performed within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Important The value of the Retry Time for Other Issues parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
Enable Throttling for Full Data Migration	Specifies whether to enable throttling for full data migration. During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads of the database servers. You can enable throttling for full data migration based on your business requirements. To configure throttling, you must configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Full Data Migration for the Migration Types parameter.
Enable Throttling for Incremental Data Migration	Specifies whether to enable throttling for incremental data migration. To configure throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.
Environment Tag	You can select an environment tag to identify the instance if needed. This setting is optional.
Configure ETL	Specifies whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: configures the ETL feature. You can enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: does not configure the ETL feature.
Monitoring and Alerting	Specifies whether to configure alerting for the data migration task. If the task fails or the migration latency exceeds the specified threshold, the alert contacts receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see the Configure monitoring and alerting when you create a DTS task section of the Configure monitoring and alerting topic.

Click Next Step: Data Verification to configure the data verification task.
For more information about how to use the data verification feature, see Configure a data verification task.
After you complete the preceding configurations, click Next: Configure Database and Table Fields at the bottom of the page. On the next page, configure the primary key and distribution columns for the migrated tables in the destination AnalyticDB for PostgreSQL instance.
Note
This page is displayed only when Migration Types is set to Schema Migration. For more information about primary key columns and distribution columns, see Data Table Management and Table Distribution Definition.

Save the task settings and run a precheck.
- To view the parameters to be specified when you call the relevant API operation to configure the DTS task, move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters.
- If you do not need to view or have viewed the parameters, click Next: Save Task Settings and Precheck in the lower part of the page.
Note
- Before you can start the data migration task, DTS performs a precheck. You can start the data migration task only after the task passes the precheck.
- If the task fails to pass the precheck, click View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, run a precheck again.
- If an alert is triggered for an item during the precheck:
  If an alert item cannot be ignored, click View Details next to the failed item and troubleshoot the issues. Then, run a precheck again.
  If the alert item can be ignored, click Confirm Alert Details. In the View Details dialog box, click Ignore. In the message that appears, click OK. Then, click Precheck Again to run a precheck again. If you ignore the alert item, data inconsistency may occur, and your business may be exposed to potential risks.

Purchase the instance.

Wait until Success Rate becomes 100%. Then, click Next: Purchase Instance.

On the Purchase Instance page, configure the Instance Class parameter for the data migration instance. The following table describes the parameters.

Section	Parameter	Description
New Instance Class	Resource Group	The resource group to which the data migration instance belongs. Default value: default resource group. For more information, see What is Resource Management?
New Instance Class	Instance Class	DTS provides instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Instance classes of data migration instances.

Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.
Click Buy and Start. In the message that appears, click OK.
You can view the progress of the task on the Data Migration page.
Note
- If a data migration task cannot be used to migrate incremental data, the task automatically stops. The Completed is displayed in the Status section.
- If a data migration task can be used to migrate incremental data, the task does not automatically stop. The incremental data migration task never stops or completes. The Running is displayed in the Status section.

Prerequisites

Precautions

Billing

Migration types

SQL operations that support incremental migration

Permissions required for database accounts

Preparations

Procedure

DTS console

DMS console