RDF System Management Manual for H-Series and J-Series RVUs (RDF 1.9)

Designing Transactions for RDF Protection
When designing applications containing transactions that update databases protected by RDF,
you must consider the following restrictions that apply to the subsystem:
• The effects of network (distributed) transactions after an RDF takeover operation
• Database operations not replicated by RDF
The sections that follow explain these restrictions.
Replicating Database Operations
Database administrators preparing to work with RDF should be aware of considerations
concerning:
• NonStop SQL Data Definition Language (DDL) operations
• NonStop SQL DDL operations with Shared Access
• Enscribe file-label modifications
• Purge operations
• Partitioned files
• Temporary disk files
NonStop SQL DDL Operations
Although RDF replicates NonStop SQL Data Manipulation Language (DML) operations, it does
not replicate NonStop SQL Data Definition Language (DDL) operations except for PURGEDATA.
Excluding PURGEDATA, the database administrator needs to perform all other DDL operations
(such as CREATE TABLE or CREATE INDEX) manually on the backup system as well as on the
primary system.
User programs should not create audited NonStop SQL tables and write to them without
coordinating table creation on the primary system with table creation on the backup system.
Recommended procedures for performing NonStop SQL DDL operations in an RDF environment
are described in “NonStop SQL/MP or NonStop SQL/MX Databases” (page 160).
Enscribe File-Label Modifications
In general, RDF does not replicate Enscribe file-label modifications.
File-label modifications in Enscribe are similar to DDL operations in NonStop SQL products, in
that the modifications do not manipulate the file itself. Instead, file-label modifications alter
attributes of the file, such as the file code, the security, the extent size, and the audit setting.
The only file-label modifications that RDF replicates are:
To create an audited Enscribe fileCREATE
To increase the number of extents for an audited Enscribe
file
ALTER MAXEXTENTS
To purge data from an audited Enscribe filePURGEDATA
To purge an Enscribe file (if REPLICATEPURGE is
enabled)
PURGE
Purge Operations
The two kinds of purge operations are PURGEDATA and PURGE. RDF replicates PURGEDATA
operations for NonStop SQL tables and Enscribe files. RDF replicates PURGE operations for
Enscribe files if REPLICATEPURGE is set on.
64 Preparing the RDF Environment