Advanced media set settings

Beyond configuring the permitted file formats for a media set, you can also configure advanced settings, such as how to write media to the media set, and how long to keep media items.

Transaction policies

The transaction policy of a media set determines how media items are added to a media set. A media set can have one of two transaction policies; transactionless or transactional.

The following details are true for a media set with transactionless policies:

• Items uploaded to the media set are immediately readable and cannot be rolled back.
• If a build writing to a transactionless media set fails, then all items that were successfully written during the build before failure will remain in the media set.
• Multiple clients can simultaneously write to a transactionless media set.
• Transactionless media set branches cannot be reset to an empty view.

The following details are true for a media set with transactional policies:

• All media items must be added to the media set from within a transaction.
• Only one transaction can be open on the branch of a media set.
• Upon committing a transaction, all items written in the transaction become readable.
• Upon aborting a transaction, all items in the transaction will be deleted.
• If a build writing to a transactional media set fails at any point, then no updates will be made to the media set.
• A maximum of 10,000 items can be written in a single transaction.

The semantics of transactional media sets are most similar to Foundry datasets. When writing incremental transforms, transactional media sets support the replace and modify write modes. Transactionless media sets only support the modify write mode.

Retention policies

You can configure a time-based retention policy for a media set, for example 14 days, for data that does not need to exist forever. Media items will only be accessible for the retention window, after which they will be permanently deleted. This is a helpful option to minimize storage costs.

Once a media item's retention window expires, it will never become accessible again, and will be deleted. For example:

• When a retention window is reduced, such as from 30 days to 7 days, all media items that are older than the new window (7 days) will immediately become inaccessible.
• When a retention window is expanded, such as from 7 days to 30 days, media items that previously expired (7 days and 1 second) will not become accessible. The same is true if retention is changed to "forever".