Operation Cache Policies

Setting an operation cache policy for mobile business object (MBO) operations gives you more control of Unwired Server interactions with the enterprise information system (EIS) to which the MBO is bound, and Unwired Server cache (CDB) updates. Fine-tuning these interactions and updates improves both Unwired Server and device application performance.

MBO operations perform specific functions based on their definition:

Read operation (MBO attributes, load arguments, and synchronization parameters) – the EIS operation used to define and initially populate the CDB (from the EIS) for the MBO. Also called a load operation.
Create, Update, Delete (CUD operations) – modify EIS data depending on the definition of the operation. Unwired Server maintains a cache (CDB) of back-end EIS data to provide differential synchronization and to minimize EIS interaction.
While this type of bulk-fetch and CDB caching are effective in reducing the number of interactions required with the EIS, and work well in some other cases (where MBO data is occasionally updated in the EIS), performance suffers if changes are initiated from Unwired Server (by way of MBO operations), or if changes are frequent.

When an operation is submitted from a device application to the EIS, the cache must be refreshed for those changes to be available to a client the next time the client synchronizes.
Entity Read operations – refresh a single instance of an MBO composite graph (MBOs in a composite relationship) in the Unwired Server cache (CDB). This type of operation can only be invoked for Create and Update operations that use an "Immediately update the cache" operation cache policy.

Operation cache policies determine how the CDB is updated after an operation executes. The operation cache policy and option combinations from which to choose to associate with MBO CUD operations include:

Immediately update the cache with Apply merge of operation input/output
(Legacy) Apply results to the cache
Immediately update the cache with Apply output of ENTITY READ operation
Invalidate the cache
None

When an MBO operation is called, its cache policy determines how operation results are applied to the CDB.

Other mechanisms used to update the CDB that are external to MBO operations, and not associated with operation cache policies include:

EIS-initiated DCN – an HTTP request to Unwired Server, in which the DCN request contains information about the changed data, or the changed data itself.
Scheduled data refresh – Unwired Server polls the EIS for changes at specified intervals.
MBO cache group – every MBO belongs to a cache group that specifies a cache refresh policy for every MBO in that group. Plan carefully to maximize cache group and cache policy efficiency. Examples include:
- A poorly designed MBO might have an operation with a cache policy that updates only the operation results to the CDB, but the MBO belongs to a cache group with an interval that refreshes the entire MBO on too short a schedule, minimizing the value of the cache policy.
- This same MBO properly designed might have a cache group that refreshes the MBO nightly, increasing Unwired Server performance by deferring load from peak usage hours.