Optimized Development Workflow

The original point of Marten was to have a persistence option that mostly got out of your way and let developers just get things done without having to spend a lot of time fiddling with database scripts or ORM configuration. To that end, the default configuration for Marten is optimized for immediate developer productivity:

var store = DocumentStore.For("connection string");

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In the configuration above, as needed, behind the scenes Marten is:

1. Checking the underlying database to check if the existing database schema matches the in memory configuration for each document type and the event sourcing, then applies any necessary database migrations at runtime
2. Generating and compiling dynamic code at runtime for each document type, compiled query type, the event sourcing, and some types of event projections

And that's (mostly) great at development time! However, the dynamic code compilation comes with a nontrivial cold start drag that's unsuitable for serverless architectures and some unnecessary sluggishness in automated testing sometimes. The automatic database migrations may be undesirable in production as it requires significant rights from the application to the underlying Postgresql database. Additionally, the automatic database migrations does require a little bit of in memory locking in the Marten code that has been problematic for folks using Marten from Blazor.

To allow for maximum developer productivity while using more efficient production options, use this option in Marten bootstrapping:

using var host = await Host.CreateDefaultBuilder()
    .ConfigureServices(services =>
    {
        services.AddMarten("connection string")

            // This feature opts into the new
            // "Optimized artifact workflow" for Marten >= V5
            .OptimizeArtifactWorkflow();
    }).StartAsync();

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When using this option, if IHostEnvironment.IsDevelopment() as it would be on a local developer box, Marten is using:

• StoreOptions.AutoCreateSchemaObjects = AutoCreate.CreateOrUpdate to detect and apply database schema migrations as needed.
• StoreOptions.GeneratedCodeMode = TypeLoadMode.Auto to generate dynamic code if necessary, or use pre-built types when they exist. This optimizes the development workflow to avoid unnecessary code compilations when the Marten configuration isn't changed.

At production time, that changes to:

• StoreOptions.AutoCreateSchemaObjects = AutoCreate.None to short circuit any kind of automatic database change detection and migration at runtime. This is also a minor performance optimization that sidesteps potential locking issues.
• StoreOptions.GeneratedCodeMode = TypeLoadMode.Auto to generate dynamic code if necessary, or use pre-built types when they exist. This ensures that the application can function in production mode even if some dynamic types are not pre-built

In production mode, Marten also disables any source code generated at runtime from being written to the file system.

To be more strict, you can also turn the code generation to Static meaning that Marten will not attempt to generate any dynamic code. This assumes that all types are pre-built ahead of time:

using var host = await Host.CreateDefaultBuilder()
    .ConfigureServices(services =>
    {
        services.AddMarten("connection string")

            // This feature opts into the new
            // "Optimized artifact workflow" for Marten >= V5
            .OptimizeArtifactWorkflow(TypeLoadMode.Static);
    }).StartAsync();

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