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Subjects & Schema Compatibilities

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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):

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Resources

Confluent has a really good article about compatibility.