Transactions And After Commit

Events support commit-aware deferral at two levels:

• dispatch-level .afterCommit()
• listener-level afterCommit: true

afterCommit is opt-in.

Dispatch-level deferral

Defer the full dispatch fan-out:

import { DB } from '@holo-js/db'
import UserRegistered from '../events/user/registered'

await DB.transaction(async () => {
  await UserRegistered.dispatch({
    userId: 'user_1',
    email: '[email protected]',
  }).afterCommit()
})

All listeners for that dispatch are scheduled for post-commit execution.

Listener-level deferral

Defer only selected listeners:

export default defineListener({
  listensTo: [UserRegistered],
  queue: true,
  afterCommit: true,
  async handle(event) {
    await readModelProjections.refresh(event.payload.userId)
  },
})

Other listeners for the same event can still run immediately.

Behavior matrix

• active transaction + afterCommit: execution is deferred until commit
• rollback: deferred listener work is discarded
• no active transaction: dispatch proceeds immediately

Nested transactions

Deferral follows DB transaction lifecycle and waits for root commit. Nested transactions or savepoints do not prematurely run deferred listeners.

Why this exists

Use afterCommit when listeners must observe committed state:

• queue workers loading fresh DB records by id
• read-model projection updates
• external side effects that should not happen if the transaction rolls back

Continue

• Dispatching Events
• Queued Listeners
• Database Transactions