Direct Load Materialization

Use direct load materialization to materialize data between different primary and replicate databases. Direct load materialization is also available between two SAP ASE databases.

Direct load materialization differs from other automatic materialization methods:

This automatic materialization method can be used for SAP ASE, Microsoft SQL Server, Oracle, and DB2 UDB primary databases.
Materialization queues are not used with direct load materialization. Data is loaded directly from a primary table into a replicate table.
Replication is suspended selectively:
- Replication of tables continues for tables that are not being materialized. DML operations on a primary table that is not being materialized are replicated into the replicate table as the DSI receives them.
- DML operations on a primary table that is being materialized are stored in a catch-up queue and applied to the replicate table after the initial materialization phase.
  Note: When DML operations in a catch-up queue are applied to the replicate table, each insert operation is converted into a delete followed by an insert. Materialization fails when an update changes the primary key.
Multiple tables can be concurrently materialized with direct load materialization.
When subscription materialization stops due to an error, regular replication of other tables is not suspended.
Multiple threads can be used to load data from one primary table to its corresponding replicate table. You can tune this multi-threaded behavior with max_mat_load_threads.
When a subscription is materialized using direct_load, you can use the configuration parameter dsi_check_unique_key to control the SAP Replication Server behavior on checking the no unique key criteria. This configuration parameter is available at the server-level through configuration replication server and at the connection-level through alter connection. Its possible values are on and off, and on is its default value.
If dsi_check_unique_key is on, the primary tables with no unique key must not have any activity until the subscription is VALID. If the activity occurs, the subscription may fail during the catch-up phase and the subscription is aborted, and marked with error. When the subscription is aborted, it must be dropped and recreated. Before recreating the subscription, cleaning up the replicate table (like truncate table) is required.
When you set dsi_check_unique_key to off, the subscription may be created successfully, but may potentially have data inconsistency. Turn off this configuration parameter only under these circumstances to ensure data is correct following subscription validation:
- There cannot be any delete statements at the primary table with no unique key.
- There cannot be any insert statements of duplicate rows at the primary table with no unique key.

Direct load materialization can be used to materialize data from:

SAP ASE to SAP ASE
SAP ASE to SAP HANA database
Microsoft SQL Server to SAP HANA database
Oracle to SAP HANA database
DB2 UDB to SAP HANA database

Direct load materialization is enabled through the direct_load option of the create subscription command. When using direct load materialization, note these restrictions for create subscription:

When the direct_load option is used, no other subscription can be created or defined at the same time for the same replicate table.
The direct_load option is for subscriptions to table replication definitions only and is used with without holdlock. It cannot be used with the without materialization or incrementally options.
The user and password options are used only with direct_load.
You cannot use the direct_load option against a logical or alternate connection. The primary connection in the replication definition and the replicate connection in the subscription must be physical connections.
The maintenance user of the primary database cannot be used in the user and password options to create subscriptions.
You cannot use other automatic materialization methods if the primary database is not SAP ASE. The only automatic materialization option for Oracle or other databases is direct load materialization.
You cannot drop a subscription with the with purge option if the replicate database is not SAP ASE.
The direct_load option is available only if the replicate SAP Replication Server site version and route version are 1571100 or later.
You can use row filtering, name mapping, customized function strings and datatype mapping with subscriptions created using the direct_load option.
If you create a subscription with the direct_load option and if the number of concurrent subscription requests exceeds num_concurrent_subs, SAP Replication Server marks the subscription as PENDING. SAP Replication Server processes the subscription only after the number of concurrent subscription requests falls below num_concurrent_subs.

Primary Database Considerations

Depending upon the primary database, SAP Replication Server either connects directly to the primary database, or connects to the Replication Agent for that primary database.
You must have Replication Agent version 15.7.1 SP100 or later to materialize data from a non-SAP ASE primary database using direct load materialization.
When invoking the create subscription command, if SAP Replication Server connects to Replication Agent, it needs to use the Replication Agent administrator login name and password.