quasar_postgres

Optional cluster-coordinated PostgreSQL Store for Quasar. Requires quasar_jobs >= 0.1.0 and < 0.2.0.

See Store contract and ownership and publishing prerequisites.

Migrations in priv/NNN_name.sql are loaded and applied strictly in version order. Regular migrations run in individual transactions protected by a PostgreSQL advisory lock. Files whose names begin with NNN_online_ run outside a transaction, on one checked-out connection protected by the same advisory lock; this supports PostgreSQL operations such as CREATE INDEX CONCURRENTLY. Applied versions are recorded in quasar_jobs_migrations, so concurrent application startup is safe and repeated calls are idempotent. Migration files must be included in the published package. Never edit an applied migration; add the next numbered file.

Retention

Retention policy lives in quasar_jobs/retention; this adapter only owns the PostgreSQL execution strategy:

import quasar_jobs/retention
import quasar_postgres/retention as postgres_retention

let policy =
  retention.new()
  |> retention.completed_for(days: 7)
  |> retention.cancelled_for(days: 30)
  |> retention.discarded_for(days: 30)

let assert Ok(cleaner) =
  postgres_retention.new(connection, policy)
  |> postgres_retention.with_batch_size(rows: 1000)
  |> postgres_retention.with_pause(milliseconds: 100)
  |> postgres_retention.with_interval(milliseconds: 60_000)
  |> postgres_retention.start

The linked cleaner deletes one bounded batch at a time with FOR UPDATE SKIP LOCKED, pauses cooperatively between batches, and uses a non-blocking PostgreSQL advisory lock to avoid overlapping delete transactions. Configure with_reporter to observe rows deleted, duration, failures, and cycle completion. Call postgres_retention.stop(cleaner) before closing the Pog pool.

Retention removes the job row. Application tables that reference quasar_jobs(id) must either use ON DELETE CASCADE, remove their data first, or archive it outside the retention transaction.