Wallaby

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Multi-tenancy (Marten) ​

Marten's conjoined multi-tenancy stores every tenant's documents in one table with a tenant_id column. Wallaby captures that column as part of the document key, so per-tenant scoping needs no scope-key selector, simply adding ScopedByTenant() reads the tenant straight from the change.

Conjoined tenancy ​

For documents with conjoined tenancy the captured key is [tenant_id, id], so equal ids across tenants stay distinct end to end. Scope a mapping by tenant with ScopedByTenant():

csharp
cdc.UseMarten()
   .UseTenantSessions();                            // lease store.QuerySession(tenantId) per tenant

sink.Map<Order>()
    .ScopedByTenant()
    .ScopedDestination(tenant => $"orders-{tenant}")   // optional index-per-tenant
    .UsingTransform(/* ... */);
  • ScopedByTenant() scopes the mapping by the change's tenant.
  • UseTenantSessions() hands each transform invocation a same-tenant IQuerySession (store.QuerySession(tenantId)), so enrichment queries only see that tenant's documents.
  • ScopedDestination(tenant => ...) routes per tenant — including deletes, whose tenant comes from the key columns. Without it, the fixed ToDestination(...) value (or the sink default) is used.

Backfills flow through the same router, so per-tenant sessions and destinations apply to backfilled documents too.

A mapping with a scoped destination flags its table for REPLICA IDENTITY FULL; ManageWallabyReplicaIdentity() lets Marten's migrations own that DDL.

Limitations ​

Only conjoined (and single) tenancy is supported; separate-database tenancy is not.