Event Multi-Tenancy

Polecat supports multi-tenancy in the event store through conjoined tenancy (shared tables) or separate database tenancy.

Conjoined Tenancy

Enable tenant isolation within shared event tables:

var store = DocumentStore.For(opts =>
{
    opts.Connection("...");
    opts.Events.TenancyStyle = TenancyStyle.Conjoined;
});

With conjoined tenancy:

• All events include a tenant_id column
• Stream queries automatically filter by tenant
• Event appending records the session's tenant ID
• The async daemon processes events per-tenant

Using Tenanted Events

await using var session = store.LightweightSession(new SessionOptions
{
    TenantId = "tenant-abc"
});

// Events are stored with tenant_id = "tenant-abc"
session.Events.StartStream<Order>(
    new OrderCreated(100m, "Widget")
);
await session.SaveChangesAsync();

// Only loads events for "tenant-abc"
var order = await session.Events.AggregateStreamAsync<Order>(streamId);

Separate Database Tenancy

Each tenant gets its own database with independent event stores:

var store = DocumentStore.For(opts =>
{
    opts.MultiTenantedDatabases(databases =>
    {
        databases.AddSingleTenantDatabase("Server=localhost;Database=events_tenant_a;...", "tenant-a");
        databases.AddSingleTenantDatabase("Server=localhost;Database=events_tenant_b;...", "tenant-b");
    });
});

With separate database tenancy:

• Each tenant has completely isolated event data
• The async daemon runs independently per database
• Schema management is independent per database

Default Tenant

When no tenant ID is specified, events are stored with tenant_id = 'DEFAULT'. In single-tenant mode, all queries use this default value.