How to handle ByteBuffer?

[Michael Bauroth <Mi...@falcom.de>]

Hi,

just a short question: When I use a single ProtocolDecoder in my 
FilterChain, must I consume all bytes in it? I ask because of while 
testing I realized increasing memory consumption over the time. I had 
the idea, that the ByteBuffer was eventually not cleared correctly from 
my side (I currently read only a part of the bytes in it).

That's why I ask: Can somebody explain in some short sentences, which 
part of Mina takes care of which elements (especially ByteBuffer) in 
this queue (Filter - Codec - IoSession) and which actions the user must 
do to keep the things running?

Best Regards
Michael

Re: How to handle ByteBuffer?

[Trustin Lee <tr...@gmail.com>]

On 4/13/06, Michael Bauroth <Mi...@falcom.de> wrote:
>
> Hi,
>
> just a short question: When I use a single ProtocolDecoder in my
> FilterChain, must I consume all bytes in it? I ask because of while
> testing I realized increasing memory consumption over the time. I had
> the idea, that the ByteBuffer was eventually not cleared correctly from
> my side (I currently read only a part of the bytes in it).


Yes, because the data you received might contain only a part of a message.
But this is not the reason why the overall memory consumption increases.  It
is because MINA pools used buffers.  The memory usage should decrease when
server is inactive for a while by garbage collector.  If you don't want
pooling, please switch the ByteBufferAllocator by calling
ByteBuffer.setAllocator(new SimpleByteBufferAllocator()).

That's why I ask: Can somebody explain in some short sentences, which
> part of Mina takes care of which elements (especially ByteBuffer) in
> this queue (Filter - Codec - IoSession) and which actions the user must
> do to keep the things running?


The buffer for a received data is allocated by SocketIoProcessor.  It is
released in an AbstractIoFilterChain IIRC.  Therefore, basically, you don't
need to manage anything.  It is never a cause of memory leak even if the
buffers are not released.  'Release' here means that the buffer goes back to
the pool.  Buffers in the pool are not GC'd automatically.  The pool expires
aged buffers, and that's where GC kicks in.

Trustin
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