Akka-超出了GC开销限制

Question

I am getting a:

java.lang.OutOfMemoryError: GC overhead limit exceeded
    at java.nio.HeapByteBuffer.asReadOnlyBuffer(HeapByteBuffer.java:117)
    at akka.util.ByteString$ByteString1.asByteBuffer(ByteString.scala:153)
    at akka.util.ByteString$ByteString1C.asByteBuffer(ByteString.scala:104)

With this Akka code:

  var buffer = ByteString.apply()
  val MsgSize = 208

  protected def onMessage(rawMsg: ByteString) = {

    // Messages under the size are not processed in while loop.  This line appends them
    // to be processed when enough data is present.
    buffer ++= rawMsg

    // Process multiple messages if present.
    while (buffer.size >= MsgSize) {
      // Process each message, leaves remainder for later processing.
    }

    // To prevent the buffer from growing uncontrollably.
    // It is possible that at some point this fails to run for a long time 
    // which could cause the out of memory exception.
    if (buffer.isEmpty) buffer = ByteString.apply()
  }

It looks like the concatenation may be the problem. Is this the right way to do this?

Answer 1

Turns out we have to do something like this:

while (buffer.size >= MsgSize) {
  val (msg, rem) = buffer.splitAt(MsgSize)

  // Process msg

  // buffer is now what remains
  buffer = rem
}

Because reading from the buffer does not increment a position.