scaffold-composite-projection

You can chain Marten projections by defining a Projection class and configuring options.Projections.CompositeProjectionFor(...) in your Marten setup. This adds Stage 1 and Stage 2 projections to establish a single, efficient read path for faster queries.

A composite projection in Marten is a pattern that chains multiple projections into a single read path. You need it when basic projections must feed outputs into dependent projections, reducing data processing time and simplifying complex projection pipelines in .NET.

To configure CompositeProjectionFor, define your Projection class and use MartenConfigurationExtensions.cs to add options.Projections.CompositeProjectionFor(...) with your Stage 1 and Stage 2 projections. Verify indexing in ConfigureIndexes to optimize throughput and query performance.

Implementing the Marten composite projection pattern requires Marten v8.18 or higher. You need a .NET application using Marten where you can define projection classes and configure the CompositeProjectionFor extension to manage staged projections and indexing.

The best way to manage indexing for staged Marten projections is to align with Marten's indexing best practices by verifying configurations in ConfigureIndexes. This optimizes throughput and query performance when Stage 1 basic projections feed into Stage 2 dependent projections.