[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Task](https://evolu.dev/docs/api-reference/common/Task) › TaskCollectionOptions

Defined in: [packages/common/src/Task.ts:2930](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Task.ts#L2930)

Options shared by [Task](https://evolu.dev/docs/api-reference/common/Task/type-aliases/Task) collection helpers.

`concurrency` controls how many Tasks run at once. It defaults to `1`. For
CPU-bound Tasks backed by workers or native parallelism, a platform
`availableParallelism()` result is often a good limit. For network or
database Tasks, choose a limit based on the transport, server, connection
pool, and rate limits.

Keep concurrency bounded. In rare cases where running every Task concurrently
is safe, use [maxPositiveInt](https://evolu.dev/docs/api-reference/common/Type/variables/maxPositiveInt).

## Extended by

- [`AllOptions`](https://evolu.dev/docs/api-reference/common/Task/interfaces/AllOptions)

## Properties

<a id="concurrency"></a>

### concurrency?

```ts
readonly optional concurrency?: Int1To100OrPositiveInt;
```

Defined in: [packages/common/src/Task.ts:2932](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Task.ts#L2932)

Maximum number of [Task](https://evolu.dev/docs/api-reference/common/Task/type-aliases/Task)s run concurrently. Defaults to `1`.