What objects can be transferred

The main objects transferred are tables and data schemas.

In addition, certain types of endpoints support a transfer of empty objects or views. There are also limits on complex data types.

Processing empty objectsProcessing empty objects

You can only transfer non-empty tables and their data but not other schema elements (indexes, external keys, etc.) between endpoints of different types (e.g., from PostgreSQL to ClickHouse®).
Auto incremental fields are also transferred, but AUTO_INCREMENT is not.

For example, the following table

CREATE TABLE `sometable` (
`id` bigint UNSIGNED NOT NULL AUTO_INCREMENT

will be transferred as

CREATE TABLE "sometable" (
"id" int8 NOT NULL

Transfers between same-type endpoints (such as from PostgreSQL to PostgreSQL) transfer empty objects as part of a schema.

Processing objectsProcessing VIEWobjects

In general, Yandex Data Transfer transfers VIEW objects (from databases where they may exist) with some restrictions:

• Replication transfers do not replicate VIEW data changes.
• Snapshot and Snapshot and increment transfers (in the copy step) between same-type endpoints, such as from PostgreSQL to PostgreSQL, only transfer a VIEW as part of a schema. VIEW data (rows) are not transferred. Schema transfers are configured by the Schema transfer setting and related settings available in some source endpoints.
• Snapshot and Snapshot and increment transfers (in the copy step) between endpoints of different types, such as from PostgreSQL to ClickHouse®, transfer VIEW objects as regular tables and not as regular views. This feature allows converting and exporting data to external databases and can be helpful when making regular transfers of the Snapshot type.

Some sources may impose additional restrictions on transfers of VIEW and similar objects. For more information about how to work with views from particular sources, see Yandex Data Transfer specifics for sources and targets.

Processing complex data typesProcessing complex data types

In transfers between endpoints of different types (e.g., from PostgreSQL to ClickHouse®), it is not recommended to transfer data of complex types (e.g., arrays of numbers). Data Transfer does not support conversion of such data, because each DBMS has its own limitations and rules for data types. When using complex types, the transfer may not work correctly.

ClickHouse® is a registered trademark of ClickHouse, Inc.