Tensorflow hangs when sess.run() is called

Question

The following code will hang (only a CTRL z gets me out).

import tensorflow as tf
import cifar10 # from https://github.com/tensorflow/models/tree/master/tutorials/image/cifar10 (both cifar10.py & cifar10_input.py)

def main():
    print 'TensorFlow version: ',tf.__version__

    with tf.Session() as sess:

    with tf.device('/cpu:0'):
        images, labels = cifar10.distorted_inputs()

    input = tf.constant([[[1, 2, 3], [5, 5, 5]], [[4, 5, 6], [7, 7, 7]], [[7, 8, 9], [9, 9, 9]]])

    one=input[0]
    print "X1 ",type(input), one
    oneval = sess.run(one)
    print "X2 ",type(one), one, type(oneval), oneval

    two=images[0]
    print "Y1 ",type(images), two
    twoval = sess.run(two)
    print "Y2 ",type(two), two, type(twoval), twoval

main()

I get the following output (with Python 2.7.5):

[gpu@centos-7-4 demo]$ python demo.py
TensorFlow version:  1.2.1
2017-07-31 16:06:45.503157: W tensorflow/core/platform/cpu_feature_guard.cc:45] >The TensorFlow library wasn't compiled to use SSE4.1 instructions, but these are available on your machine and could speed up CPU computations.
2017-07-31 16:06:45.503182: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE4.2 instructions, but these are available on your machine and could speed up CPU computations.
2017-07-31 16:06:45.503187: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use AVX instructions, but these are available on your machine and could speed up CPU computations.
Filling queue with 20000 CIFAR images before starting to train. This will take a few minutes.
X1  class 'tensorflow.python.framework.ops.Tensor'> Tensor("strided_slice:0", shape=(2, 3), dtype=int32)
X2  class 'tensorflow.python.framework.ops.Tensor'> Tensor("strided_slice:0", shape=(2, 3), dtype=int32) <type 'numpy.ndarray'> [[1 2 3] [5 5 5]]
Y1  class 'tensorflow.python.framework.ops.Tensor'> Tensor("strided_slice_1:0", shape=(24, 24, 3), dtype=float32)
^Z

Anyone have any suggestions (or solutions)?

If anyone is interested in the background, my ultimate goal is to convert the tensor returned by distorted_inputs() into a set of JSON objects. So the naive plan is to iterate through each element of images and pull out the values.

Answer 1

I found the answer here Printing tensorflow tensor in Python hangs forever

Key was the two lines:

coord = tf.train.Coordinator()
threads = tf.train.start_queue_runners(sess=sess, coord=coord)

Answer 2

我在TF 1.7中遇到了这个问题，降级为1.3，它可以正常工作。