Occasional "SetTransaction with non empty batcher" error when running CassandraTransactionalKeyValue workload in debug build

[robertpang]

When CassandraTransactionalKeyValue workload in debug build, "SetTransaction with non empty batcher" error is seen occasionally.

$ java -jar ~/code/yugabyte/java/yb-loadtester/target/yb-sample-apps.jar -workload CassandraTransactionalKeyValue -num_threads_read 8 -num_threads_write 4 -nodes 127.0.0.1:9042

yb-tserver.err:

F0529 10:46:23.895027 310902784 session-internal.cc:77] SetTransaction with non empty batcher
Fatal failure details written to /tmp/yugabyte-local-cluster/node-1/disk-1/yb-data/tserver/logs/yb-tserver.FATAL.details.2018-05-29T10_46_23.pid51703.txt
F20180529 10:46:23 ../../../../../src/yb/client/session-internal.cc:77] SetTransaction with non empty batcher
    @        0x1150e2c8b  google::LogDestination::LogToSinks()
    @        0x1150e1daf  google::LogMessage::SendToLog()
    @        0x1150e2775  google::LogMessage::Flush()
    @        0x1150e25f3  google::LogMessage::~LogMessage()
    @        0x1115197b6  yb::client::YBSessionData::SetTransaction()
    @        0x111414d0c  yb::client::YBSession::SetTransaction()
    @        0x10fd180fe  yb::ql::QLEnv::CommitTransaction()
    @        0x10f41ca43  yb::ql::Executor::FlushAsyncDone()
    @        0x10f4416fb  yb::internal::RunnableAdapter<>::Run()
    @        0x10f441639  yb::internal::InvokeHelper<>::MakeItSo()
    @        0x10f4415d7  yb::internal::Invoker<>::Run()
    @        0x10fd1a41b  yb::Callback<>::Run()
    @        0x10fd15cdc  yb::ql::QLEnv::ResumeCQLCall()
    @        0x10fd21aa9  yb::internal::RunnableAdapter<>::Run()
    @        0x10fd219fc  yb::internal::InvokeHelper<>::MakeItSo()
    @        0x10fd219aa  yb::internal::Invoker<>::Run()
    @        0x10e55afae  yb::Callback<>::Run()
    @        0x10e55aefd  yb::cqlserver::CQLInboundCall::TryResume()
    @        0x10e592bbf  yb::cqlserver::CQLServiceImpl::Handle()
    @        0x113c045c6  yb::rpc::ServicePoolImpl::Handle()
    @        0x113c059aa  yb::rpc::(anonymous namespace)::InboundCallTask::Run()
    @        0x113c0583d  yb::rpc::TasksPool<>::WrappedTask::Run()
    @        0x113c19cf1  yb::rpc::(anonymous namespace)::Worker::Execute()
    @        0x113c1b131  _ZNSt3__128__invoke_void_return_wrapperIvE6__callIJRNS_6__bindIRKMN2yb3rpc12_GLOBAL__N_16WorkerEFvvEJRKPS7_EEEEEEvDpOT_
    @        0x113c1af69  _ZNSt3__110__function6__funcINS_6__bindIRKMN2yb3rpc12_GLOBAL__N_16WorkerEFvvEJRKPS6_EEENS_9allocatorISE_EEFvvEEclEv
    @        0x11072ac1b  std::__1::function<>::operator()()
    @        0x114a4117f  yb::Thread::SuperviseThread()
    @     0x7fff7e036661  _pthread_body
    @     0x7fff7e03650d  _pthread_start
    @     0x7fff7e035bf9  thread_start

[robertpang]

Fixed in commit 9bbed84.