Astera Data Virtualization solution supports the caching feature that enables users to create a local copy of the sources that are being used on the Virtual Data Model. The cache data is updated at a specified frequency, which is set during the design process. This helps users save time and cost by reducing the number of calls made to the source system, which can be API sources, database servers, etc. Moreover, caching also improves query performance since the data would be retrieved from the cache database instead of the source system.
Creating a Cache Schedule
The virtualization project in Centerprise contains a folder for schedules. This can be used to create a schedule, which can be further used inside the cache properties wizard of any entity. Users can add a new schedule to the project by right-clicking on the Schedules folder in the Project Explorer. Different entities on a virtual data model can have different schedules as long as they are in the same virtualization project. Once added, the schedule document will open automatically.
In this schedule document, users can select the cache frequency and start time (where applicable). Once saved, it can be used inside cache properties of any entity.
Enable Caching in a Virtual Data Model
Users can enable caching in two ways:
- By right-clicking on the Entity object. This will enable caching for a single entity.
- By clicking on the Toolbar command. This will enable caching for all entities simultaneously.
The second option will apply default cache settings by using the first schedule in the project for all entities. Users may change it by opening cache properties or using the Set Cache Schedule command in the right-click menu.
Cache Table and Schema Name
Enabling caching for any entity will enable the Cache Properties command as well. Users may modify cache settings by opening the cache properties wizard. This wizard gives the options to set/modify cache table and schema names on the second page.
Cache Entity Layout
On the third page of the cache properties wizard, users will find the cache database entity layout. This layout can be used to create a cache table for any entity in the cache database during the deployment process.
Users can also find the Virtual Entity Layout, on the first page of the cache properties wizard, for comparison with the Cache Entity Layout. Both layouts are built from the entity source layout, which can be modified.
Incremental Cache Load and Scheduling
The fourth page of the cache properties wizard allows users to pick a schedule from the project and assign it to an entity for caching. On the same page, users can set incremental cache load. Incremental load will only load the updated or newly added records in the source database to the cache table.
Cache Table Indexes
Cache properties wizard also allows users to create indexes for the cache table to improve the query performance at runtime.
Cache Database Information
Once the cache properties have been set, the next step is to provide the database information where all the caching entities would be created. It is a pre-requisite for deploying a virtual data model.