V7.1 Enhancements - IBM AS/400e User Handbook Manual

IBM Licensed Programs: Database Products
Data can be a subset for distribution through column and row specifications, replicating only
the data needed. Unique to DataPropagator Relational is the ability to subselect for joins and
unions, allowing a subset according to a value not in the table being replicated. This can be a
key requirement when replicating to mobile laptops from normalized databases where most
values are not redundantly stored.
An Apply instance can process many subscriptions at a single site. Multiple Apply instances
can run concurrently at different sites/platforms, each processing different numbers and types
of subscriptions from the same source. Each subscription can have different definitions,
refresh criteria, and timing.
The On-Demand replication capability offers a solution to the challenge of infrequent and
unpredictable connections present in the mobile computing community. Data transfers are
initiated from the mobile unit where control should be based. This implementation allows
downloading from a central server (pulling) or uploading for consolidated processing
(pushing).

V7.1 Enhancements

Replicating Large Objects
DB2 Universal Database supports large object (LOB) data types, which include binary LOB
(BLOB), character LOB (CLOB), and double-byte character LOB (DBCLOB). This section
refers to all of these types as LOB data.
The Capture program reads the LOB descriptor to determine if any data in the LOB column
has changed and thus should be replicated, but does not copy the LOB data to the CD tables.
When a LOB column changes, the Capture program sets an indicator in the CD tables. When
the Apply program reads this indicator, it then copies the entire LOB column (not just the
changed portions of LOB columns) directly from the source table to the target table.
To allow the Capture program to detect changes to LOB data, include the DATA CAPTURE
CHANGES keywords when you create (or alter) the source table.
Because a LOB column can contain up to two gigabytes of data, ensure that you have
sufficient network bandwidth for the Apply program. Likewise, your target tables must have
sufficient disk space to accommodate LOB data.
BIGINT Data Type
This new supported data type allows replication of big 8-byte integer data types. This permits
the storage and replication of integers larger than 2.1 GB for specialized application needs.
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AS/400e System Handbook