diff --git a/python/ray/rllib/agents/impala/impala.py b/python/ray/rllib/agents/impala/impala.py
index 9221e3764..94294a1fc 100644
--- a/python/ray/rllib/agents/impala/impala.py
+++ b/python/ray/rllib/agents/impala/impala.py
@@ -64,7 +64,9 @@ DEFAULT_CONFIG = with_common_config({
     "replay_proportion": 0.0,
     # number of sample batches to store for replay. The number of transitions
     # saved total will be (replay_buffer_num_slots * sample_batch_size).
-    "replay_buffer_num_slots": 100,
+    "replay_buffer_num_slots": 0,
+    # max queue size for train batches feeding into the learner
+    "learner_queue_size": 16,
     # level of queuing for sampling.
     "max_sample_requests_in_flight_per_worker": 2,
     # max number of workers to broadcast one set of weights to
diff --git a/python/ray/rllib/agents/ppo/appo.py b/python/ray/rllib/agents/ppo/appo.py
index d64621d82..d5f9f4fa4 100644
--- a/python/ray/rllib/agents/ppo/appo.py
+++ b/python/ray/rllib/agents/ppo/appo.py
@@ -35,6 +35,7 @@ DEFAULT_CONFIG = with_base_config(impala.DEFAULT_CONFIG, {
     "num_sgd_iter": 1,
     "replay_proportion": 0.0,
     "replay_buffer_num_slots": 100,
+    "learner_queue_size": 16,
     "max_sample_requests_in_flight_per_worker": 2,
     "broadcast_interval": 1,
     "grad_clip": 40.0,
diff --git a/python/ray/rllib/optimizers/async_samples_optimizer.py b/python/ray/rllib/optimizers/async_samples_optimizer.py
index 60b4eb691..1af548af5 100644
--- a/python/ray/rllib/optimizers/async_samples_optimizer.py
+++ b/python/ray/rllib/optimizers/async_samples_optimizer.py
@@ -24,7 +24,6 @@ from ray.rllib.utils.window_stat import WindowStat
 
 logger = logging.getLogger(__name__)
 
-LEARNER_QUEUE_MAX_SIZE = 16
 NUM_DATA_LOAD_THREADS = 16
 
 
@@ -49,6 +48,7 @@ class AsyncSamplesOptimizer(PolicyOptimizer):
               broadcast_interval=1,
               num_sgd_iter=1,
               minibatch_buffer_size=1,
+              learner_queue_size=16,
               _fake_gpus=False):
         self.learning_started = False
         self.train_batch_size = train_batch_size
@@ -73,10 +73,12 @@ class AsyncSamplesOptimizer(PolicyOptimizer):
                 num_data_loader_buffers=num_data_loader_buffers,
                 minibatch_buffer_size=minibatch_buffer_size,
                 num_sgd_iter=num_sgd_iter,
+                learner_queue_size=learner_queue_size,
                 _fake_gpus=_fake_gpus)
         else:
             self.learner = LearnerThread(self.local_evaluator,
-                                         minibatch_buffer_size, num_sgd_iter)
+                                         minibatch_buffer_size, num_sgd_iter,
+                                         learner_queue_size)
         self.learner.start()
 
         assert len(self.remote_evaluators) > 0
@@ -230,11 +232,12 @@ class LearnerThread(threading.Thread):
     improves overall throughput.
     """
 
-    def __init__(self, local_evaluator, minibatch_buffer_size, num_sgd_iter):
+    def __init__(self, local_evaluator, minibatch_buffer_size, num_sgd_iter,
+                 learner_queue_size):
         threading.Thread.__init__(self)
         self.learner_queue_size = WindowStat("size", 50)
         self.local_evaluator = local_evaluator
-        self.inqueue = queue.Queue(maxsize=LEARNER_QUEUE_MAX_SIZE)
+        self.inqueue = queue.Queue(maxsize=learner_queue_size)
         self.outqueue = queue.Queue()
         self.minibatch_buffer = MinibatchBuffer(
             self.inqueue, minibatch_buffer_size, num_sgd_iter)
@@ -275,12 +278,13 @@ class TFMultiGPULearner(LearnerThread):
                  num_data_loader_buffers=1,
                  minibatch_buffer_size=1,
                  num_sgd_iter=1,
+                 learner_queue_size=16,
                  _fake_gpus=False):
         # Multi-GPU requires TensorFlow to function.
         import tensorflow as tf
 
         LearnerThread.__init__(self, local_evaluator, minibatch_buffer_size,
-                               num_sgd_iter)
+                               num_sgd_iter, learner_queue_size)
         self.lr = lr
         self.train_batch_size = train_batch_size
         if not num_gpus:
diff --git a/test/jenkins_tests/run_multi_node_tests.sh b/test/jenkins_tests/run_multi_node_tests.sh
index ce96887bb..573052fa1 100755
--- a/test/jenkins_tests/run_multi_node_tests.sh
+++ b/test/jenkins_tests/run_multi_node_tests.sh
@@ -214,14 +214,14 @@ docker run --rm --shm-size=${SHM_SIZE} --memory=${MEMORY_SIZE} $DOCKER_SHA \
     --env CartPole-v0 \
     --run IMPALA \
     --stop '{"training_iteration": 2}' \
-    --config '{"num_gpus": 0, "num_workers": 2, "min_iter_time_s": 1, "num_data_loader_buffers": 2, "replay_proportion": 1.0}'
+    --config '{"num_gpus": 0, "num_workers": 2, "min_iter_time_s": 1, "num_data_loader_buffers": 2, "replay_buffer_num_slots": 100, "replay_proportion": 1.0}'
 
 docker run --rm --shm-size=${SHM_SIZE} --memory=${MEMORY_SIZE} $DOCKER_SHA \
     python /ray/python/ray/rllib/train.py \
     --env CartPole-v0 \
     --run IMPALA \
     --stop '{"training_iteration": 2}' \
-    --config '{"num_gpus": 0, "num_workers": 2, "min_iter_time_s": 1, "num_data_loader_buffers": 2, "replay_proportion": 1.0, "model": {"use_lstm": true}}'
+    --config '{"num_gpus": 0, "num_workers": 2, "min_iter_time_s": 1, "num_data_loader_buffers": 2, "replay_buffer_num_slots": 100, "replay_proportion": 1.0, "model": {"use_lstm": true}}'
 
 docker run --rm --shm-size=${SHM_SIZE} --memory=${MEMORY_SIZE} $DOCKER_SHA \
     python /ray/python/ray/rllib/train.py \
@@ -448,6 +448,14 @@ docker run --rm --shm-size=${SHM_SIZE} --memory=${MEMORY_SIZE} $DOCKER_SHA \
     --stop '{"training_iteration": 2}' \
     --config '{"num_workers": 2, "use_pytorch": true, "sample_async": false}'
 
+docker run --rm --shm-size=${SHM_SIZE} --memory=${MEMORY_SIZE} $DOCKER_SHA \
+    python /ray/python/ray/rllib/train.py \
+    --env PongDeterministic-v4 \
+    --run IMPALA \
+    --stop='{"timesteps_total": 40000}' \
+    --ray-object-store-memory=500000000 \
+    --config '{"num_workers": 1, "num_gpus": 0, "num_envs_per_worker": 64, "sample_batch_size": 50, "train_batch_size": 50, "learner_queue_size": 1}'
+
 python3 $ROOT_DIR/multi_node_docker_test.py \
     --docker-image=$DOCKER_SHA \
     --num-nodes=5 \