Skip to content

data-attribute-db-sync-overview.md

Latest commit

 

History

History
36 lines (27 loc) · 1.71 KB

data-attribute-db-sync-overview.md

File metadata and controls

36 lines (27 loc) · 1.71 KB
Raw

Data Attribute → Postgres sync (overview)

Automatically mirror a workflow data attribute to a cell (row + column) of a user-owned Postgres table. The iWF data attribute stays the source of truth; the database cell is a mirror.

  • Load on start — when the workflow starts, the data attribute is loaded from its mapped column.
  • Sync on mutation — whenever the data attribute is mutated in a state's execute method, the new value is written back to the same column.
DataSource ds = /* your configured, pooled DataSource */;

DataAttributeDef.create(
    String.class,
    "status",
    DbAttributeSync.of(ds, "public.orders", "id",
        (workflowId, persistence) -> new CellLocation(workflowId, "status_col")));

How it works (3 lines)

  1. Client.startWorkflow starts at a load system state that SELECTs each mapped column and sets the data attribute, then transitions to your real starting state (input passes through).
  2. When a state's execute mutates a mapped data attribute, the worker reroutes the decision through a sync system state that UPDATEs the column, then continues to your original decision.
  3. iWF persists the data attribute first, then the DB write happens — so a DB failure retries only the sync step, never your execute. Neither system state is registered; both are worker-internal.

Key limitations (v1)

  • Fixed-key data attributes only (not createByPrefix).
  • Sync fires on execute mutations only (not waitUntil).
  • Load fires for workflows started through the registered Client.
  • The mapped column stores the data attribute's JSON — use a text/jsonb column.

See the detailed guide: data-attribute-db-sync.md.