mark yoffe wrote:
Hi
i have been running scenario where several consumers connect to the same
public queue (topic)
the consumers connect via subscription manager.
i have run several scenarios where multiple listeners use the same
connection (different sessions) and scenario where listeners each have their
own connection
all of this has been run on TRUNC versions
a while ago i started experiencing a serious down downgrade in performance
when using such a scenario
in the past the use of multiple listeners enabled me to enhance performance
but currently it appears that i can achieve a faster performance while using
1 listener application
in the past when several listeners used a shared queue - the message flow
to between the consumers was not even (if using x listener one would expect
to receive 1/x messages per listener)
this problem/feature was corrected to support a pretty even distribution of
the task
as far as i can tell around the time this enhancement was made(it might not
be connected but..)
the performance started going down, and it is not a small difference
using one listener i can achieve a speed of X for 100k messages per second
using five listeners i experience a serious down grade of performance to ~5X
for 100k messages per second
this was not the case in the past and i am at a loss regarding this problem
does anyone know , how this can be resolved
Sounds like https://issues.apache.org/jira/browse/QPID-1280 for which I
don't have a quick fix unfortunately as yet. It was caused by some
necessary changes to the locking (specifically to prevent deadlocks when
using RDMA, but this may also have improved the 'fairness' of allocation).
I can give you a one-line patch that should revert back to the earlier
performance if you like. I have some ideas for a proper fix but they
were going to be too involved for the M4 timeframe I'm afraid.
Adding more publishers also helps I found.
