Performance Improvement with Delta Tracking and Caching¶
You can use delta change tracking (short as delta tracking) and data caching to significantly improve the performance of the mobile service.
OData delta tracking is a method by which a client obtains changes from an OData service without downloading the entire data set. Set up the
track_deltas parameter in your application configuration file when you configure your defining queries. If your OData service supports delta query protocol to track changes, the provided delta links are automatically used to track changes and you do not need to configure delta tracking. When possible, use an OData service that supports delta query protocol.
Delta change tracking sends only changed data to the client, rather than the entire data set. This significantly decreases the load on the back end and is especially useful when performance is critical.
If your OData service does not support delta tracking, the default delta tracking setting in the application configuration file tracks deltas using the mobile service. This improves performance on the client, while tracking deltas using the OData service improves performance over the entire network.
If your OData service has limited support for delta tracking, for example, deltas are configured to expire after a set period of time, using the
ALWAYSsetting for delta tracking in the application configuration file helps replace missing delta tracking functionality.
If all or most of your data is continuously changing so that you expect to be downloading the full data set during every download, enabling delta tracking does not improve performance. For example, if you download the temperature value for sensors in 1000 offices, using delta tracking does not decrease the amount of data downloaded during a download and turning off delta tracking may increase performance.
To minimize the load on the OData service and possibly improve performance, cache data that is shared by numerous users on the mobile service. For example, cache data from a defining query that returns the same results to multiple users. Do not cache data from a defining query that returns different results to each user. Set up the
is_shared_data parameter when you configure your defining queries in application configuration file.