title: gnuplot timefmt error from csv input "Bad time format"
body: <p>I'm trying to plot a 500 MB csv file of two columns as below:</p>
  
  <pre><code>ID,"timestamp"
  1,"2016-02-09 14:46:52.683"
  2,"2016-02-09 14:47:02.687"
  3,"2016-02-09 14:47:09.896"
  4,"2016-02-09 14:47:12.702"
  5,"2016-02-09 14:47:22.663"
  6,"2016-02-09 14:47:32.668"
  7,"2016-02-09 14:47:42.68"
  8,"2016-02-09 14:47:52.676"
  9,"2016-02-09 14:48:02.661"
  </code></pre>
  
  <p>I've written a gnuplot script but am unsure where I'm going wrong. I've followed other posts too. What am I missing?</p>
  
  <p>I think that the milliseconds data sometimes has few values could be an issue - but again, I'm not sure how to resolve.</p>
  
  <p>Many thanks in advance! Chris</p>
  
  <pre><code>set datafile separator ","
  set key autotitle columnhead
  set xdata time
  set timefmt '"%Y-%m-%d %H:%M:%.6S"'
  set format x "%Y-%m-%d %H:%M:%.6S"
  # set xrange ['"2016-04-01 00:00:00.000000"':'"2016-05-01 17:00:00.000000"']
  plot "~/timestampi.csv" u 2:1
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>Terminal type set to 'qt'
  gnuplot&gt; load "~/g.p"
           "/home/chrisb/g.p", line 6: warning: Bad time format in string
           "/home/chrisb/g.p", line 6: warning: Bad time format in string
           "/home/chrisb/g.p", line 7: warning: Skipping data file with no valid points
  
  gnuplot&gt; plot "~/timestampi.csv" u 2:1 w l
                                            ^
           "/home/chrisb/g.p", line 7: all points y value undefined!
  
  gnuplot&gt; 
  </code></pre>