HP NonStop G-Series - Manual (Page 43)

SDR Operations
HP NonStop SQL DDL Replicator User’s Guide —545799-005
4-3
DDL Capture Artifacts
•
Marker Files
SDR Depot Files
SDR depot files are automatically created by SDR as needed. A depot file is an
audited Enscribe key-sequenced file. A depot file is created on each primary database
volume that has a SQL object (table, index, so on) that is the target of a captured DDL
statement.
The name of the subvolume where a depot file is stored is a combination of the
reserved name ZASDR and the Expand node number. The depot filename is always
SDRDEPOT.
For example, the depot file $DATA.ZASDR004.SDRDEPOT is created for SQL objects
residing on $DATA, on the primary RDF system with an Expand node number of 4.
The replication of the SDRDEPOT files to the backup system is described below in
Creating the SDR Depot Files on the Backup on page 4-8.
Stop RDF Update Audit Records
Stop RDF Update (SRU) audit records are described in (RDF 5 – Performing Shared
Access DDL Operations). When SDR is not installed, SRU audit records are generated
by SQL to signal the completion of a WITH SHARED ACCESS DDL operation. When
RDF updaters encounter an SRU record, they stop at an appropriate location to allow
you to manually perform the DDL operation on the backup system and then manually
restart RDF updating.
The SRU record contains the name of the SQL table or index that was the target of the
WITH SHARED ACCESS operation. The file name is used by RDF for informational
purposes only; it is written to the EMS log to alert the operator to the need to manually
replicate the DDL and restart RDF updating.
When SDR is installed, NonStop SQL no longer generate SRU audit records for WITH
SHARED ACCESS operations, because SDR replicates the DDL operations
automatically.
You will, however, see SRU messages produced by RDF in the EMS log, because
SDR generates SRU messages to coordinate its operation with RDF. For operational
purposes, these EMS messages should be ignored.
Marker Files
Marker files are used to satisfy an artificial requirement of RDF that each file specified
in a Stop RDF Update audit record must exist. If the file does not exist, the RDF
Extractor aborts and cannot be restarted without reinitializing RDF.
Marker files are created in the same subvolume as depot files. They are empty,
unaudited, and unstructured Enscribe files, with names like