Enhancements to Replication Definition Version in SAP Replication Server 15.7.1 SP303

The proper way to modify a replication definition is to execute the rs_send_repserver_cmd stored procedure at the primary database with the primary table locked. In the past, you had to lock the primary table by using the corresponding database command. For example, if you want to modify the replication definition called authors for the primary SAP ASE table authorinfo, you need to run the following commands:

begin transaction

lock table authorinfo in exclusive mode

exec rs_send_repserver_cmd ‘alter replication definition authors drop zip’

commit tran

Now if you are working with a primary SAP ASE database, you can also lock the primary table with a new parameter called @ptable in this stored procedure. For instance, the following is equivalent to the above example.

exec rs_send_repserver_cmd ‘alter replication definition authors drop zip’, authorinfo

Locking the primary table when executing the rs_send_repserver_cmd stored procedure ensures the new replication definition version is created either before or after a transaction. This is especially important when there are large or long-running transactions on the primary database. If the replication definition is altered while the transaction is in progress, a replication definition version may be dropped from the system before the data associated with it can be processed by SAP Replication Server. This may result in the shutdown of the Data Server Interface (DSI). To avoid such issue, lock the primary table when you modify a replication definition.

Note that the @ptable parameter is available only when the primary database is SAP ASE. For other database types, please lock the primary table by using the corresponding database command as shown above. Just make sure the primary table is locked when you modify a replication definition at the primary database.

• Keep all replication definition versions

You might have already started wondering what if …

    “Somehow I cannot lock the primary table when the replication definition commands are being executed.”

    “I need to modify a replication definition directly within SAP Replication Server.”

Now you have another option, which is keeping all old versions in the system by using the new parameter, preserve_repdef_versions, in the configure replication server command within SAP Replication Server. For example,

Configure replication server

set preserve_repdef_versions to ‘on’

Set the value of the preserve_repdef_versions parameter to on to keep old replication definition versions in the system. This way, if you modify a replication definition, older versions are not deleted from the system unless you drop them manually.

• Drop a replication definition version

With the value of preserve_repdef_versions set to on, if you no longer need an old replication definition version, you need to remove it from your system by using the drop replication definition command.

For example, let’s drop the version 0x010100660000035f for the authors replication definition.

drop replication definition 0x010100660000035f for authors

• Create a replication definition version

If you forgot to lock the primary table when executing the rs_send_repserver_cmd stored procedure, or if you executed the alter replication definition command directly within SAP Replication Server without setting the value of preserve_repdef_versions to on, you might run into missing replication definition version issues. In this case, you can recreate the missing replication definition version:

create replication definition <repdef_version_id> for <replication_definition> as <repdef_version_id_to_be_copied>

Please don’t use this command to create the newest replication definition version, which is not allowed. The purpose of this command is to recreate replication definition versions dropped from the system while relevant data is still in the replication system.

1. Alter the current replication definition so that the definition is identical to the missing replication definition version. For example:

   alter replication definition authors add zip

   This alteration creates a new version of the authors replication definition, which is 0x010400660000035f. This version of replication definition is identical to the missing version 0x010200660000035f.

2. Recreate the missing version of 0x010200660000035f from the current version of 0x010400660000035f by using the new command as shown below.

   create replication definition 0x010200660000035f for authors as 0x010400660000035f

   The missing version 0x010200660000035f is recreated in the system.

3. Reissue the command that failed due to the missing replication definition version. For example, resume the DSI connection.
4. When the data associated with the version of 0x010200660000035f is no longer in the replication system, drop the version if necessary.

   drop replication definition 0x010200660000035f for authors

5. Alter the replication definition back to make it identical to the replication definition version before the alteration in step 1, which is 0x010300660000035f. For example:

   alter replication definition authors drop zip

   This alteration creates a new replication definition version of 0x010500660000035f. It should be identical to the version of 0x010300660000035f.

• View the creation date of a replication definition version

Run the rs_helprepversion command to review the creation date of a replication definition version to help you decide whether a particular version is old and can be safely removed from the system.

rs_helprepversion authors

go

Repdef Version                                         Repdef Version                    Active      Active          Create

Name                                                          ID                                            Inbound  Outbound   Date

————————————————–   ——————————-      ———–   ————–  —————————————–

Authors                                                        0x0102006500000065      Yes          Yes              Feb 4 2016 2:53:25.157219PM

rs_drp010100650000006556b3d665  0x0101006500000065       No           No               Feb 4 2016 2:51:49.076000PM

rs_drp010000650000006556b3d605  0x0100006500000065       No           No               Feb 4 2016 2:50:57.716000PM