Limitations and considerations

You should be aware of the following limitations and considerations when using Google Cloud SQL for PostgreSQL as a source:

• The database name cannot include a semi-colon (;).
• Capturing changes while the database is in Hot Standby mode is not supported.
• Replication of multiple tables with the same name but a different case (e.g. table1, TABLE1 and Table1) may cause unpredictable behavior and is therefore not supported.
• The PostgreSQL read replica (in a High Availability environment) is supported from PostgreSQL 16 only.
• Change processing of TRUNCATE operations is not supported.
• Deferred Constraints are not supported.

• Unique Indexes with CASE expressions are not supported.

• REPLICA IDENTITY support:

  • If FULL is used, before-image values will be replicated for all table columns. Only when using this mode is it possible to redefine the target index.

  • If DEFAULT is used, replication is supported only when a table contains a Primary key. Additionally, only before-images of Primary Key columns will be replicated.

  • USING INDEX is supported only when the specified Unique Index is the only unique constraint for the table (meaning that the table does not have a Primary Key or another Unique Index). In this case, it is supported exactly the same as the DEFAULT value described above.

  • As Replicate does not verify the REPLICA IDENTITY value, make sure you define the correct value.

• The “Start Process Changes from Timestamp” run option is not supported.

• Change processing of [CREATE | ALTER | DROP] table DDLs are supported unless they are held in an inner function/procedure body block or in other nested constructs.

  For example, the following change will not be captured:

  CREATE OR REPLACE FUNCTION attu.create_distributors1() RETURNS void

  LANGUAGE plpgsql

  AS $$

  BEGIN

  create table attu.distributors1(did serial PRIMARY KEY,name varchar(40) NOT NULL);

  END;

  $$;

• When Support partitioned tables in CDC is enabled in the Advanced tab, the following DDLs are not supported:

  • Drop partition
  • Detach partition
  • Attach partition - with data
• An UPDATE operation that involves two partitions (moving a record between partitions) will be applied to the target using DELETE and INSERT operations.

• When using the Parallel Load feature, table segmentation according to partitions or sub-partitions is not supported.

• When using filters that do not contain a Primary Key, DELETE operations will not be captured.

• When capturing changes to source tables, a RENAME TABLE operation will be captured only if it is preceded by a DML operation.

• PostGIS data types are not supported.

• Forced failover is a feature of Azure Database for PostgreSQL – Flexible Server. If forced failover occurs when replicating data from Azure Database for PostgreSQL – Flexible Server, the task will stop and will need to be reloaded.

• The SQL MERGE command introduced in PostgreSQL 15.x has not been certified.

• The AR_H_USER header column is not supported.

Unsupported data types