Distributed
application of transactions for high volume adaptive replication (HVAR) to SAP ASE databases
maximizes parallel processing within transactions to improve replication performance for the
data server interface (DSI) thread.
With distributed application of transactions, SAP Replication Server
separates commands within transactions into multiple groups and applies the command
groups in parallel to the replicate database instead of applying each command serially.
Use the dt_apply parameter to enable distributed application of
transactions either at the server level for all connections or at the connection level
for specific connections. A connection-level configuration overrides the server-level
configuration.
Ensure that SAP Replication Server has sufficient memory and processing resources, as
enabling parallel processing consumes more of these resources. You can control the
number of worker threads available to the global task manager which can then assign the
threads to process tasks scheduled by the distributed application of transactions in the
DSI thread.
Note: The replicate SAP ASE data server requires a
separate license and configuration for distributed transaction management (DTM) to
support distributed application of transactions from SAP Replication Server. See
SAP ASE System Administration Guide: Volume 2 > Distributed Transaction
Management > Enabling DTM features > Installing a license key.
Platform Support
dt_apply is available on all supported SAP Replication Server
platforms except for Linux on IBM p-Series and Microsoft Windows. See the SAP
Replication Server Release Bulletin for supported platforms.
Limitations to the Distributed Application of Transactions in the DSI Thread for HVAR
- You can enable distributed application of transactions only
after you enable HVAR to SAP ASE databases.
- SAP Replication Server disables distributed application of
transactions only if you enable full incremental compilation for large
compilable transactions during high volume adaptive replication. The
limitation does not apply to smaller compilable transactions that do not use
incremental compilation whether or not you have enabled full incremental
compilation. See Full Incremental Compilation for HVAR.
- SAP Replication Server automatically disables distributed application of
transactions for the DSI thread in the RSSD.
- SAP Replication Server automatically disables distributed
application of transactions for non-compilable transactions that HVAR cannot
process. Instead, replication reverts to log-order row-by-row continuous
replication. See HVAR Processing and Limitations.
- Distributed application of transactions benefits transaction profiles where
there is replication of multiple tables which can then take advantage of
parallelism.
- Distributed application of transactions requires more memory and processing
resources because of the parallel processing of transactions.