[FLINK-3673] Annotations for code generation

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: API / Type Serialization System
• Labels: auto-unassigned gsoc2016
• Assignee: Unassigned
• Reporter: Gabor Horvath
• Due: 10/Jul/16
• Created: 29/Mar/16 10:11
• Updated: 27/Apr/21 23:25

Description

Annotations should be utilized to generate more efficient serialization code.

Planned improvements:

• Using never null annotations on a field, the serialized representation can omit the 1 byte null tags and the serializer code handling this tag.
• Using never null annotiation on the POJO, we can omit the top level null tag.
• Making a POJO final we can omit the subclass tag.

The very same annotations can be used to make the getLength method much smarter.

Code generation is a prerequisite, to avoid runtime checks which could make the common codepath (without annotations) slower.

I could also annotate some internal Flink types to make them more efficient.

The main risk: it would break savepoints created with a Flink version that did not have annotation. We could either introduce a compatibility mode, or force users to recreate those save points.

Issue Links

• Blocked: FLINK-3671 Code generation for POJO serializer