Stay organized with collections Save and categorize content based on your preferences.
Known limitations for using a PostgreSQL database as a source include:
The pglogical extension doesn't support the replication of generated columns for PostgreSQL 12+.
Changes to table structures (DDL) aren't replicated through standard DDL commands, but only with commands executed using the pglogical extension used for replication. This includes changes to enum types.
For example, pglogical provides a function pglogical.replicate_ddl_command that allows DDL to be run on both the source database and replica at a consistent point. The user running this command on the source must already exist on the replica.
In order to replicate data for new tables, you must use the pglogical.replication_set_add_table command to add the new tables to existing replication sets.
To learn more about DDL replication while the migration is in progress, see the section on migration fidelity.
For tables that don't have primary keys, Database Migration Service supports migration of the initial snapshot and INSERT statements during the change data capture (CDC) phase. You should migrate UPDATE and DELETE statements manually.
Database Migration Service doesn't migrate data from materialized views, just the view schema. To populate the views, run the following command: REFRESH MATERIALIZED VIEW view_name.
The SEQUENCE states (for example, last_value) on the new AlloyDB destination might vary from the source SEQUENCE states.
UNLOGGED and TEMPORARY tables aren't and can't be replicated.
Large Object data type isn't supported. More details in the section on migration fidelity.
Database Migration Service doesn't support migrating from read replicas that are in recovery mode.
Database Migration Service doesn't support Amazon RDS sources where the AWS SCT extension pack is applied.
If other extensions and procedural languages exist in the source database, or if their versions aren't supported, then when you test or start the migration job, it will fail.
Databases that are added after the migration job has started aren't migrated.
information_schema).pg, for example, pg_catalog. For the full list of PostgreSQL catalogs that begin with pg, see PostgreSQL system catalogs in the PostgreSQL documentation.If encrypted databases require customer-managed encryption keys to decrypt the databases, and if Database Migration Service doesn't have access to the keys, then the databases can't be migrated.
However, if customer data is encrypted by the pgcrypto extension, then the data can be migrated with Database Migration Service (because AlloyDB supports the extension).
Database Migration Service also supports migrating data from encrypted Amazon Aurora or Amazon RDS databases because these databases handle decryption transparently in their services. For more information, see Encrypting Amazon Aurora resources and Encrypting Amazon RDS resources.
The destination AlloyDB database is writable during the migration to allow DDL changes to be applied if needed. Take care not to make any changes to the database configuration or table structures which might break the migration process or impact data integrity.
Trigger behavior depends on how they were configured. The default behavior is they won't trigger, but if they were configured using the ALTER EVENT TRIGGER or ALTER TABLE statement and the trigger state is set to either replica or always, then they will trigger on the replica during replication.
Functions with security definer will be created by alloydbexternalsync in AlloyDB primary. When it's executed by any users, it will be executed with the privileges of alloydbexternalsync which has alloydbsuperuser and alloydbreplica roles. It's better to restrict use of a security definer function to only some users. To do that, the user should revoke the default PUBLIC privileges and then grant execute privilege selectively.
Private Service Connect interfaces connectivity method is only supported for migrating to existing destination instances. If you want to use private IP connectivity and migrate to a new destination instance, use VPC peering.
For more information on AlloyDB for PostgreSQL clusters and instances, see AlloyDB for PostgreSQL overview.
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2025-08-14 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["Database Migration Service supports the migration of initial snapshots and `INSERT` statements for tables without primary keys, but `UPDATE` and `DELETE` statements must be manually migrated."],["Certain PostgreSQL features are not supported during migration, including `UNLOGGED` and `TEMPORARY` tables, Large Object data types, and read replicas in recovery mode."],["Database Migration Service migrates all tables and schemas except for `information_schema` and tables beginning with `pg`, and does not migrate information about users and user roles."],["While the destination AlloyDB database remains writable during migration, modifications to the database configuration or table structures should be avoided to prevent issues."],["There are quotas for the amount of migration jobs and connection profiles that can exist at any given time, set to 1,000 and 2,000 respectively, requiring deletion to create space for more."]]],[]]
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4