Subjects & Schema Compatibilities

Compatibilities

Long story short, there are 7 modes of compatibility handled by the Schema Registry:

tip

Transitive means the whole lineage of schemas is verified. Not transitive means only the last 2 schemas are verified.

• Full + Transitive: The safest, recommended.
  • Add/Delete optional fields only.
  • You can ONLY add optional fields (basically, all your fields are optional!): the consumer must explicitly handle the case each field is not present
  • You can upgrade the Consumers or Producers like you want, no worries.
• Backward + Transitive
  • Delete fields or Add optional fields only.
  • Upgrade Consumers first (in case a mandatory field was deleted).
• Forward + Transitive:
  • Add fields or Delete optional fields only.
  • Upgrade Producers first (produce new mandatory fields before consumers)
• Full: Almost the safest.
  • Add/Delete optional fields only.
  • You can ONLY add optional fields (basically, all your fields are optional!): the consumer must explicitly handle the case each field is not present
  • You can upgrade the Consumers or Producers like you want, no worries.
• Backward
  • Delete fields or Add optional fields only.
  • Upgrade Consumers first (in case a mandatory field was deleted).
  • Check compatibility only with the previous version
• Forward
  • Add fields or Delete optional fields only.
  • Upgrade Producers first (produce new mandatory fields before consumers).
  • Check compatibility only with the previous version
• None: Be careful.
  • No compatibility checking. You can push incompatible schemas as you want.
  • Be sure to know what you're doing

You can see them in Conduktor, at the different places where you can change it (global or per subject):

Resources

Confluent has a really good article about compatibility.