Add multitenancy module: Hibernate 7 @TenantId vs schema-per-tenant (shared pool + search_path, pool per tenant), JWT tenant filter, isolation failure modes on PostgreSQL 17 (Hibernate 7.4.14.Final, Spring Boot 4.1.2)

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b4VQVEJWetTT1dYzyJ
2026-10-29 05:52:26 +00:00
parent ef2d2aa8ea
commit 98f4ed7411
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+# @TenantId on PostgreSQL (PostgreSQL 17.11), Hibernate 7.4.14.Final
+
+== DDL Hibernate generated (read back from the catalog)
+column amount numeric nullable=YES
+column id bigint nullable=NO
+column number character varying nullable=YES
+column tenant_id character varying nullable=NO
+unique UNIQUE (tenant_id, number)
+
+== insert: nobody sets tenant_id in Java
+-- as acme: save(INV-1)
+   sql> insert into invoice (amount,number,tenant_id) values (?,?,?)
+   entity.tenantId after save = acme
+-- as globex: save(INV-1) - same invoice number, allowed by UNIQUE(tenant_id, number)
+   sql> insert into invoice (amount,number,tenant_id) values (?,?,?)
+   ids: acme INV-1=1, globex INV-1=2 (one IDENTITY column shared by all tenants)
+
+== reads are filtered
+-- as acme: findAll()
+   sql> select i1_0.id,i1_0.amount,i1_0.number,i1_0.tenant_id from invoice i1_0 where i1_0.tenant_id = ?
+   rows = 2, numbers = [INV-1, INV-2]
+-- as globex: findById(acme's id 1)
+   sql> select i1_0.id,i1_0.amount,i1_0.number,i1_0.tenant_id from invoice i1_0 where i1_0.id=? and i1_0.tenant_id = ?
+   result = Optional.empty
+
+== bulk HQL is scoped too
+-- as acme: update Invoice set amount = 0
+   sql> update invoice i1_0 set amount=0 where i1_0.tenant_id = ?
+   rows updated = 2 (globex's row untouched)
+
+== what @TenantId does NOT cover: native SQL
+-- as acme: native query  select count(*) from invoice
+   result = 3  (acme owns 2 rows; the native query saw every tenant)
+
+== no tenant set
+-- strict resolver (throws when TenantContext is empty): repo.findAll() with no tenant
+   org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction  <- caused by com.ankurm.multitenancy.tenant.MissingTenantException: no tenant in TenantContext: refusing to open a tenant-scoped session
+-- lenient resolver (returns null): repo.findAll() with no tenant
+   org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction  <- caused by org.hibernate.HibernateException: SessionFactory configured for multi-tenancy, but no tenant identifier specified
+
+== writing a row for a different tenant than the session's
+-- as acme: new Invoice with tenantId manually set to globex, saveAndFlush
+   org.springframework.dao.DataIntegrityViolationException: assigned tenant id differs from current tenant id [globex != acme] for entity com.ankurm.multitenancy.discriminator.Invoice.tenantId  <- caused by org.hibernate.PropertyValueException: assigned tenant id differs from current tenant id [globex != acme] for entity com.ankurm.multitenancy.discriminator.Invoice.tenantId