When working with Avro schemas, it’s crucial to understand the different compatibility modes to ensure seamless data evolution. Here are the four modes you can choose from:
FORWARD Compatibility 🏃♂️➡️
- Forward compatibility means that data written with an older schema can be read with a newer schema.
- Use this when you want to add new fields with default values or delete fields.
BACKWARD Compatibility ⬅️🏃♂️
- Backward compatibility ensures that data written with a newer schema can be read with an older schema.
- Opt for this mode when you want to remove fields or make a new field optional by providing a default value.
NONE Compatibility ❌
- No compatibility guarantees are provided. This means that schemas can be independently evolved without any restrictions.
- This is the “free-for-all” mode, where you don’t need to worry about schema evolution.
FULL Compatibility ✅
- Full compatibility combines both forward and backward compatibility.
- Choose this to ensure that new data can be read with old schemas and vice versa, which is ideal for maximum flexibility.
Remember, the choice of compatibility mode affects how your data can evolve over time. Choose wisely to avoid any potential headaches with data processing down the line! 😌
Isn't the FULL compatibility too restrictive?
FULL compatibility mode in Avro can indeed be seen as restrictive because any changes made to the schema must be both forward and backward compatible. This means:
- New fields added must have default values.
- Fields removed must have been optional (i.e., had a default value).
- No changes are allowed that would prevent an older schema from reading data written with the new schema, and vice versa.
The restrictiveness of FULL compatibility is actually its strength, as it ensures the highest level of schema discipline. It’s designed for scenarios where data integrity and consistency are paramount, and where schema evolution needs to be managed very carefully.
However, it might not be suitable for all use cases, especially if you anticipate frequent and significant changes to your schema. In such cases, a less restrictive mode like BACKWARD or FORWARD might be more appropriate, as they allow for more flexibility in evolving your schema without breaking existing data contracts.
Ultimately, the choice of compatibility mode should be based on your specific data governance needs and how you plan to manage schema evolution over time. FULL compatibility is best for long-term stability, while other modes offer more flexibility for iterative changes. 🔒✨
Which mode should you choose for a new app?
Choosing the right Avro compatibility mode for a new app when you’re unsure about its evolution can be challenging. Here’s a general guideline:
- FULL Compatibility: If you want to enforce strict schema evolution rules from the start and are okay with the restrictiveness it imposes, then FULL compatibility with all optional fields having default values is a safe choice. It ensures that any future changes won’t break existing data pipelines.
- FORWARD or BACKWARD Compatibility: If you expect your schema to evolve but want to maintain some level of compatibility, you might opt for FORWARD or BACKWARD compatibility. This allows for some flexibility while still maintaining a degree of control over schema evolution.
- NONE Compatibility: If you want complete freedom to change the schema without any restrictions, NONE compatibility would be the way to go. However, this could lead to issues with data compatibility if not managed carefully.
For a new app, starting with FULL compatibility might seem restrictive, but it can help prevent complex issues in data processing as the app evolves. As you gain more understanding of how your app’s data usage patterns develop, you can consider relaxing the compatibility mode if necessary.
Remember, the choice isn’t permanent; you can start with one mode and switch to another as your needs change. The key is to document your schema changes meticulously and communicate them to all stakeholders to ensure smooth transitions. 🔍📝