Bug 1609227

Description of problem:
When overwriting messages in priority ring queue due to both message priority and ring feature, memory leak happens. It is due to:

/usr/src/debug/qpid-0.18/cpp/src/qpid/broker/PriorityQueue.h :

    /** FIFO index of all messsagse (including acquired messages)  for fast browsing and indexing */
    MessageDeque fifo;

where this deque is accumulating more and more messages.

I *think* the reason is PriorityQueue::erase purges "messages" (map of dequeues that was seen always right during the reproducer) but not "fifo" (dequeue that was growing over time, with many DELETED or REMOVED messages there).

This leak is present on primary and also backup broker in HA cluster, as well as on a standalone broker.

This leak is present on 0.18-49 but fixed in 1.36 (where, contrary, a similar leak is present - will file soon)


Version-Release number of selected component (if applicable):
qpid-cpp 0.18-49
NOT present in 1.36


How reproducible:
100%


Steps to Reproduce:
- create ring priority queue, send messages with priority 9 and then in a loop with prio 7 (or any other lower prio)

queue=Ring_1
qpid-receive -a "${queue}; {create:always, node:{ x-declare:{arguments:{'qpid.max_count':1000, 'qpid.policy_type':'ring', 'x-qpid-priorities':10}}}}" 

qpid-send --priority=9 -m 1000 -a "${queue}"

while true; do date; qpid-send --priority=7 -m 1000 -a "${queue}"; done

- observe memory footprint
- optionally, in gdb, check "fifo" deque size of that queue


Actual results:
- memory grows over time
- "fifo" deque grows over time


Expected results:
- no mem.leak


Additional info:
in gdb:

(gdb) thread 6
[Switching to thread 6 (Thread 0x7f853d2fa7a0 (LWP 28590))]#0  0x00007f853addc1c3 in epoll_wait () from /lib64/libc.so.6
(gdb) frame 4
#4  0x000000000040fbdb in qpid::broker::QpiddDaemon::child (this=<value optimized out>) at posix/QpiddBroker.cpp:149
149	        brokerPtr->run();
(gdb) p brokerPtr->px->queues
$1 = {queues = std::map with 26 elements = {.... ["Ring_1"] = {px = 0x7f84f01419a0, pn = {pi_ = 0x7f84f012e690}}}, 
  lock = {<boost::noncopyable_::noncopyable> = {<No data fields>}, rwlock = {__data = {__lock = 0, __nr_readers = 0, __readers_wakeup = 12, __writer_wakeup = 0, __nr_readers_queued = 0, 
        __nr_writers_queued = 0, __writer = 0, __shared = 0, __pad1 = 0, __pad2 = 0, __flags = 0}, __size = "\000\000\000\000\000\000\000\000\f", '\000' <repeats 46 times>, __align = 0}}, 
  counter = 1, store = 0x197a840, events = 0x0, parent = 0x197d6a0, lastNode = false, broker = 0x197ab10}
(gdb) p *((qpid::broker::PriorityQueue *) ((qpid::broker::Queue*) 0x7f84f01419a0)->messages->_M_ptr)
$2 = {<qpid::broker::Messages> = {_vptr.Messages = 0x7f853d0d57b0}, levels = 10, messages = std::vector of length 10, capacity 10 = {std::deque with 0 elements, std::deque with 0 elements, 
    std::deque with 0 elements, std::deque with 0 elements, std::deque with 0 elements, std::deque with 0 elements, std::deque with 0 elements, std::deque with 86097 elements = {
      0x7f83c4779948, .....}, std::deque with 13903 elements = {0x7f84f9a89bc8, .....}, std::deque with 0 elements}, 
  fifo = {<qpid::broker::Messages> = {_vptr.Messages = 0x7f853d0d52f0}, messages = std::deque with 110111542 elements = {{payload = {px = 0x7f84feacf010}, 


See the fifo is "std::deque with 110111542 elements" (while "messages" has 100k messages in 2 priority buckets)