Configure the database

The journal, query journal, and snapshot store use the same database provider by default. In F#, choose the provider with Fcqrs.connect and pass the connection to Fcqrs.actor.

open FCQRS.FSharp

let connection =
    Fcqrs.connect FCQRS.Actor.DBType.Sqlite "Data Source=app.db;"

// An empty IConfiguration accepts the embedded Akka.NET defaults.
let config = Microsoft.Extensions.Configuration.ConfigurationBuilder().Build()
let loggerFactory = Microsoft.Extensions.Logging.LoggerFactory.Create(fun _ -> ())
let api = Fcqrs.actor config loggerFactory (Some connection) "MyCluster"

// C#: this host-builder overload is SQLite-backed.
using Microsoft.Extensions.DependencyInjection;

services.AddFcqrs("Data Source=app.db;", "MyCluster");

The C# AddFcqrs overload and ActorApi.Create currently create a SQLite connection definition. To use another provider from a C# host, override the three persistence plugin connection and provider settings through configuration as shown in the configuration reference.

Choose a provider

DBType supports these provider families:

Changing the F# DBType configures all three persistence stores and enables table initialization:

let connection =
    Fcqrs.connect FCQRS.Actor.DBType.PostgreSQL
        "Host=localhost;Database=app;Username=app;Password=…"

Use SQLite for local development and deployments where one process owns the file. A multi-node cluster needs a database reachable by every node.

Do not commit production credentials in HOCON or source code. Supply them through the application's secret provider or environment-specific configuration.

Verify the connection

On a new database, start the application and confirm that journal, query journal, and snapshot tables are created. Send one command, stop the process, start it again, and send another command to the same aggregate id. The returned event version should advance, proving that recovery read the existing journal.

Then test the database account with automatic schema creation disabled if production policy requires pre-provisioned tables. The account still needs the read and write permissions required by the Akka.NET persistence plugins.

Other persistence settings

Change snapshot cadence with config:akka:persistence:snapshot-version-count, or use an aggregate or saga SnapshotPolicy. The default is every 30 persisted events.

FCQRS merges application configuration over its embedded HOCON. The Configuration reference lists the merge order, plugin settings, runtime keys, and cluster overrides.