Re: [infinispan-dev] DIST.retrieveFromRemoteSource

On Sun, Feb 5, 2012 at 5:56 PM, Bela Ban<bban(a)redhat.com> wrote: > > > On 2/5/12 4:40 PM, Dan Berindei wrote: > > >>> Remember that a message might be retransmitted, so it is placed into a >>> retransmit buffer. If M1 has destination A and M2 has destination B, and >>> we send M1 first (to A), then change M1's destination to B, and send it, >>> everything is fine. However, if we later get a retransmit request from >>> B, we'd resend the message to A instead ! This is just 1 example, >>> modifications of headers is another one. >>> >>> Note that the copy does *not* copy the buffer (payload) itself, but only >>> references it, so this is fast. Of course, nobody is supposed to modify >>> the contents of the buffer itself... >>> >> >> I wasn't clear enough, but I didn't mean we should reuse the entire >> Message object. I meant we should copy the Message but not the buffer >> or the headers. I see now that protocols may be adding new headers, so >> it wouldn't be safe to reuse the headers collection. >> >> I think this line in >> RequestCorrelator.sendRequest(RequestCorrelator.java:152) means that >> the contents of the buffer is copied in the new message, not just the >> buffer reference: >> >> Message copy=msg.copy(true); > > > No, this does *not* copy the buffer, but simply references the same buffer. > Aha, I thought copy_buffer == true meant "copy the contents" and copy_buffer == false meant "share the contents". I see copy_buffer == true actually means "copy the reference, share the contents" and copy_buffer == false means "don't copy anything".

I will modify our CommandAwareRpcDispatcher to use GroupRequest and see how they compare, then we can continue this discussion with the results.