Federated reads vs unbundled writes
Federated Reads vs Unbundled Writes — Two Ways to Combine
No single engine fits all patterns: unify queries, or sync writes.
FEDERATED — unify reads
one query interface (Trino,
Postgres foreign wrappers)
apps tap engines directly,
or combine via the layer
relational tradition: clean
semantics, complex build
writes are
the hard part
UNBUNDLED — sync writes
event log + CDC link systems
unbundles index maintenance
ordered log, idempotent apply
Unix tradition: small tools,
one pipe-like API above
loose coupling, safe faults
Why unbundle wins:
the hard problem is keeping WRITES in sync, not mapping reads.
ordered log + idempotent writes beat XA across strange systems.
breadth, not depth: cover more workloads, not one workload faster.