# Why is my 'triggerable' Akka source's buffer overflow strategy being ignored?

**URL:** <https://discuss.akka.io/t/why-is-my-triggerable-akka-sources-buffer-overflow-strategy-being-ignored/1493>\
**Category:** Akka Streams & Alpakka\
**Tags:** scala\
**Created:** [July 5, 2018, 2:33pm UTC](https://discuss.akka.io/t/why-is-my-triggerable-akka-sources-buffer-overflow-strategy-being-ignored/1493 "2018-07-05T14:33:54Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![erip](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.akka.io/erip/32/504_2.png) [@erip](https://discuss.akka.io/u/erip)\
**Post date:** [July 5, 2018, 2:33pm UTC](https://discuss.akka.io/t/why-is-my-triggerable-akka-sources-buffer-overflow-strategy-being-ignored/1493/1 "2018-07-05T14:33:54Z")

</div>

I have an actor source which will emit jobs when a trigger message is received:

```auto
import akka.NotUsed
import akka.stream.scaladsl.Source
import com.typesafe.scalalogging.LazyLogging

/**
  * Reads from a source when a trigger is received and then pushes the message downstream.
  *
  * @param elements the source to be read on trigger.
  * @param triggerSource the source which will receive trigger messages.
  * @tparam Message the type of message the read-source will produce.
  * @tparam Trigger the type of message the trigger-source will accept.
  */
class TriggeredSourceReader[Message, Trigger](
  protected val elements: Source[Message, NotUsed],
  protected val triggerSource: Source[Trigger, NotUsed]
) extends LazyLogging {

  val source = elements.zipWith(triggerSource)((msg: Message, trigger: Trigger) ⇒ {
    logger.debug(s"Releasing $msg")
    msg
  })

}

```

I set its buffer size to `n` and make the flow return instantly. Despite this, I find that when I send more than `n` messages (at a rate of 1 msg/s), the messages after the first `n` are ignored.

I tried setting the overflow strategy to `fail`, but it was ignored completely.

What am I overlooking here?

---

<div class="post-metadata">

**Author:** ![erip](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.akka.io/erip/32/504_2.png) [@erip](https://discuss.akka.io/u/erip)\
**Post date:** [July 5, 2018, 2:46pm UTC](https://discuss.akka.io/t/why-is-my-triggerable-akka-sources-buffer-overflow-strategy-being-ignored/1493/2 "2018-07-05T14:46:57Z")

</div>

My flow forgot to send the `Trigger` message to the source!