Performance Considerations

 

Updateable rowsets may be opened for either with optimistic or pessimistic locking.  (See the section on Lock modes for more information.)  Best performance is obtained using pessimistic locking. However, in multi user environments, optimistic locking might be required.

Applications may choose to open data sets for updating in either immediate update mode or delayed update mode.   (See the section on Update Modes for more explanation.). In delayed update mode, changes to the data source are queued up and transmitted to the server in batch fashion. Fewer transmissions are made to the IOM server compared to the immediate update mode.  Therefore, performance is expected to be better in delayed update mode.   By default, IOM provider rowsets are opened for read-only. To open a data set in immediate update mode, pass a property value of VARIANT_TRUE for DBPROP_IRowsetChange on the IOpenRowset::OpenRowset method(). To open a data set in delayed update mode, pass a property value of VARIANT_TRUE on the IOpenRowset::OpenRowset method() for both DBPROP_IRowsetChange and DBPROP_IRowsetUpdate. Immediate update mode is recommended for batch processing tasks.  Delayed update mode is recommended for interactive applications.