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Concurrency & Locking

EntityTS provides both optimistic concurrency checks and pessimistic row-level database locks.

Optimistic Concurrency Control​

Use @Version or @ConcurrencyCheck to automatically guard against lost updates:

@Entity({ tableName: 'products' })
export class Product {
  @PrimaryKey()
  id!: number;

  @Column()
  price!: number;

  @Version()
  version!: number;
}

If another request modifies the entity concurrently, EntityTS throws a DbUpdateConcurrencyException.

Pessimistic Locking​

Acquire exclusive or shared locks during query execution:

// PostgreSQL: SELECT ... FOR UPDATE SKIP LOCKED
// MSSQL: SELECT ... WITH (UPDLOCK, ROWLOCK, READPAST)
const nextJob = await db.jobs.where('status', '=', 'pending').lock('skip-locked').firstOrDefault();

Supported lock modes:

  • 'pessimistic' (FOR UPDATE / WITH (UPDLOCK, ROWLOCK))
  • 'shared' (FOR SHARE / WITH (HOLDLOCK, ROWLOCK))
  • 'no-wait' (FOR UPDATE NOWAIT / WITH (UPDLOCK, NOWAIT))
  • 'skip-locked' (FOR UPDATE SKIP LOCKED / WITH (READPAST))