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Best Practices

  • Object names across the offline enabled object services must be unique.
    • Tables created on the device while setting up the sync environment do not handle duplicate names.
  • Gateway Request Timeouts
    • Volt MX Cloud Gateway on AWS imposes a request timeout of 30 seconds, by default. This can be extended to 60 seconds with the help of a cloud support ticket.
    • It means every upload or download request must finish within 60 seconds.
    • Implement the recommendations made under Syncing large data sets for overcoming this issue.

  • Offline Objects work with both the project formats of Iris (that is Free-Form and Reference Architecture).

    • Offline objects APIs work in both the project types. However, the generated code for models supports limited functionality.

    • While using generated models, we recommended you to use the Offline Object APIs in conjunction with the generated models in order to utilize the full functionality of the generated models and the Offline Object APIs.

    • Duplicate Records

    • If the data runs into a request time-out, the client may sync the same data multiple times. In this case, the data is sent to the back end but the client does not receive a response. This might result in creating duplicate records.

      To overcome this issue, use the Upload Cache feature.

  • If there is an ongoing sync session for an entity, another sync session for the same entity is not allowed to prevent potential data inconsistencies.

  • Background Sync in the latest versions of iOS
    • The latest versions of iOS impose background execution limits on the background apps. To enable the background sync, follow the procedure described here.
  • In the case of a composite primary key, only one of the primary keys can be auto-generated.
  • Multi-parent hierarchical uploads are not supported.
  • Auto-generated primary keys of the type, String are not supported.
  • Device-side encryption cannot be enabled on the existing sync environment. It should be enabled during the initial setup or by resetting the device by using the reset API.
  • Relationships between objects that belong to different object services are not supported on the device’s Read API.
  • Syncing to database views as the backend is not supported.
  • Batching support for RDBMS is available from V8 SP4 April FP Foundry release.

  • Limit the size of a single record to 1 MB or less due to the following reasons:

    • SQLite fails to read records larger than 1MB from the device database.

    • We recommend to save binary content as a file on the filesystem and its path in the database column instead of saving the entire content as a base64 encoded string into the database column.

    • The collection/array of records is not supported in sync flows between the Volt MX Foundry server and the back end.
    • Use Progress Callbacks to update UI of progress in sync because users typically expect visual feedback of the long-running processes. Further, this provides stats of the sync process, providing info of the data synced.
    • If minor data model changes do not need the client app updates, use the incrementalSetup feature.