HP NonStop G-Series - Manual (Page 50)

SDR Operations
HP NonStop SQL DDL Replicator User’s Guide —545799-005
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SDR and RDF Takeover
the target name, but does not replicate some secondary reference, SDR signals an
error and waits for operator intervention.
Appendix A, SQL DDL Statements provides information on how each DDL statement is
translated.
Executing DDL
When the DDL has been successfully translated, SDR executes it on the backup
database.
If the command drops a SQL object, then SDR refers to the REPLICATEPURGE
setting of RDF. If the setting is ON, the DROP is executed; otherwise SDR issues an
EMS message and awaits operator intervention.
When executing replicated DDL, SDR reports SQL errors in the EMS log and waits for
the operator to take action. See
Controlling Replication in SDR Monitoring and Control .
If the DDL statement alters or drops a table that does not exist on the backup, the
operation is discarded and the RDF updaters are restarted.
When executing the DDL for a CREATE operation, SDR assumes the user identity that
executed the primary system DDL. Thus, the same user will own both primary and
backup SQL objects. You can configure the user ids that SDR should use for CREATE
operations. See
Setting CREATE Ownership and Security on page 3-5 for details.
SDR executes the DDL for other types of access as the SUPER user, just as RDF
does for data replication. You can configure SDR to perform replicated DDL operations
other that CREATE as the user who performed the operation on the primary. See
Setting the User ID for Replicated DDL Operations on page 3-6 for details.
Restarting RDF Update
Once the backup DDL is successfully executed, or canceled by the operator, SDR
sends RDF a message to restart its updaters. SDR then waits for the next RDF
“Update NSA Stopped” state.
SDR and RDF Takeover
SDR operation in a planned or unplanned RDF takeover is completely automatic; no
operator intervention is required.
Note. Many RDF configurations have excluded SQL catalog subvolumes. If your DDL
references a catalog on an excluded subvolume of a replicated volume, SDR will still attempt
to replicate the operation. It will use the same subvolume on the RDF backup volume.
But, if the backup catalog does not exist, SDR (and RDF) will wait for operator intervention.
You will have to either create the catalog manually or CANCEL the DDL replication.
This rule does not apply to CREATE CATALOG or DROP CATALOG on a subvolume that is
excluded in RDF. Also, in this situation, AUTOCREATECATALOG will not create a catalog.