Combining Load and Synchronization Parameters

Combine parameter settings to control how data is cached in the CDB, and filtered and returned to a device application.

Since data refresh and synchronization is controlled through parameters, design and implement load and synchronization parameters for efficient data control, especially where large sets of data are involved, or Unwired Server and device applications may perform poorly. For example:

Unwired Server – defining load parameters that load too much enterprise information system (EIS) data into the CDB at a given time can impact performance and, in some cases, generate memory errors (java.lang.OutOfMemoryError). Define load parameters to divide data into smaller segments so data loads efficiently. Otherwise, you may have to increase the server’s JVM heap size to accommodate the extra load.
Device application – synchronization parameters limit CDB to device application data. If you do not define synchronization parameters, a client may download all data in the CDB (for a particular MBO), and, in the worst case, cause the device application to crash. Define synchronization parameters to divide data into manageable segments so every synchronization finishes quickly.

These results are based on the customer table in the sampledb database in the My Sample Database connection profile.

Parameters	Result
No load or synchronization parameters are defined.	All table data is downloaded to the device. The SQL definition is: `select * from sampledb.dba.customer`
The region synchronization parameter is defined, but not used as a load parameter.	Only customers from a specific region are downloaded to the device. Typically, region is paired with a personalization key. For example, a sales representative living and working in the western region is interested only in customers from that region. The SQL definition is: `select cust_id, cust_name, region from sampledb.dba.customer where region=:region`
The region parameter is defined, used as a load parameter, and as a synchronization parameter.	Occurs if data refresh requires a region parameter and a synchronization parameter. This scenario is more likely for Web service and SAP MBOs than for database MBOs.
Load parameters are mapped to username and password personalization keys, and a separate synchronization parameter is mapped to region.	Refresh data only for the authenticated user, but synchronize based on the region: `select cust_id, cust_name, region from sampledb.dba.customer where region=:region`, for user A.