__cxa_pure_virtual called in run_event_loop()

#0  0x00007ff5144211f7 in raise () from /usr/lib64/libc-2.17.so

#1  0x00007ff5144228e8 in abort () from /usr/lib64/libc-2.17.so

#2  0x00007ff514d58405 in __gnu_cxx::__verbose_terminate_handler() () from /opt/couchbase/lib/libstdc++.so

#3  0x000000000044a40a in backtrace_terminate_handler () at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/utilities/terminate_handler.cc:82

#4  0x00007ff514d561d6 in ?? () from /opt/couchbase/lib/libstdc++.so

#5  0x00007ff514d56221 in std::terminate() () from /opt/couchbase/lib/libstdc++.so

#6  0x00007ff514d564b6 in __cxa_rethrow () from /opt/couchbase/lib/libstdc++.so

#7  0x000000000044a42c in log_handled_exception () at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/utilities/terminate_handler.cc:38

#8  backtrace_terminate_handler () at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/utilities/terminate_handler.cc:71

#9  0x00007ff514d561d6 in ?? () from /opt/couchbase/lib/libstdc++.so

#10 0x00007ff514d56221 in std::terminate() () from /opt/couchbase/lib/libstdc++.so

#11 0x00007ff514d56f6f in __cxa_pure_virtual () from /opt/couchbase/lib/libstdc++.so

#12 0x00000000004616fe in run_event_loop (c=c@entry=0x7ff47e944c00, which=which@entry=6) at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/daemon/connections.cc:159

#13 0x000000000043d831 in thread_libevent_process (fd=<optimized out>, which=<optimized out>, arg=0x7ff5015394a0) at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/daemon/thread.cc:317

#14 0x00007ff515baa37c in event_process_active_single_queue.isra.26 () from /opt/couchbase/lib/libevent_core.so.2.1.8

#15 0x00007ff515bad7cf in event_base_loop () from /opt/couchbase/lib/libevent_core.so.2.1.8

#16 0x000000000043be94 in worker_libevent (arg=0x7ff5015394a0) at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/daemon/thread.cc:209

#17 0x00007ff516a90387 in run (this=0x7ff5014efd30) at /home/couchbase/jenkins/workspace/couchbase-server-unix/platform/src/cb_pthreads.cc:59

#18 platform_thread_wrap (arg=0x7ff5014efd30) at /home/couchbase/jenkins/workspace/couchbase-server-unix/platform/src/cb_pthreads.cc:72

#19 0x00007ff51644fe25 in start_thread () from /usr/lib64/libpthread-2.17.so

#20 0x00007ff5144e434d in clone () from /usr/lib64/libc-2.17.so

void run_event_loop(Connection* c, short which) {

    const auto start = ProcessClock::now();

    c->runEventLoop(which);

    const auto stop = ProcessClock::now();